wit's end

[damienk]

My Atomic 4 and I have been fighting for the past few months now. And I am about to shoot myself.

One day motoring out, I noticed that the temp gauge was all the way maxed out. I worried and turned the engine off immediately. The gauge didn't move. turned it back on again with no problem after a 5 hours sail, not a problem, gauge still at max temp. For what I know, it might have been stuck there for months. A few days later, I try to start the engine: it starts, then dies. Again, starts and dies sooner. Until the point it doesn't start. If I wait some, it starts sometimes, and dies within a few seconds.
I thought it would be fuel related. I replaced EVERYTHING fuel related. Doesn't start. Then a month passed by (I was busy), and now I am trying again.
Now, the engine starts for a few seconds ONLY with starting fluid, otherwise it only cranks. The carb has been replaced 3 times (with backup carbs, then rebuilt carb) with no difference. Fuel pump is new. Fuel filter new. Fuel line new. New thermostat, new temp sending unit (now it has a low temp reading, but I guess it's normal since it doesn't even start). I even removed the head and the manifold, cleaned it all real good, checked the valves (seemed OK), put it all back together with new gaskets. Still, doesn't start (only with starting fluid). Occasionally, a neighbor passes by, and says in a deep voice "it's your carb". But how many time can I replace and rebuild a carb with no improvement and it still being the carb? I am about to shoot myself or blow this engine up. Any idea anyone?

( I do get a good spark. The compression ain't the best at 100-75-75-100. It was there before I removed the head, it is still there, no change. I figured that it isn't great but it is should be good enough for the engine to run...?)

[Al Schober]

First thought is 'Are you getting gas?'
I'd drain what's in the carb, dump it in the parking lot, and see if it burns. Sounds like you may have a load of non-gas in your fuel tank.
Quick check is to connect a small tank of known good gas to your engine and see if you can get it running. If it runs, attack your fuel supply issue. If it doesn't, back to the carb.

[Dave Neptune]

I agree with Al. Stop throwing parts at it and start some good diagnosis. The check Al mentioned is the absolute best for determining contaminated fuel. The engine will idle and work under light loads just fine with gravity feed.

If the engine runs with fresh gravity fed fuel you can eliminate the carb. Then it will be time to be sure you have pressure and clean fuel. Drain about a pint or more into a clear glass container and see if it is only fuel or is there water at the bottom of the jar.

You also need to know if there is fuel pressure at the carb. A cheap inline gage is fine. This will eliminate a good deal of guess work.


Dave Neptune

[damienk]

Thanks guys for the ideas! The gas I would think is still good, it is fresh from 1 month ago and I added MMO and marine fuel stabil to it at that time. I actually kind of know it is good now, because I just came back from the boat, where I decided in a desperate attempt to create a 4th carburetor out of the 3 I already tried. Combined a few parts, checked the specs on MMI, and the miracle happened. It started first try. I can't believe it but I am so, so, so happy about it.
However, I do still have a problem: the engine is overheating (I stopped it after 3 to 5 minutes of purring perfecty as I noticed an alarming temperature of over 220 and climbing). This tells me I don't have the full story yet, and that when I started having issues a couple months ago, it was indeed overheating (and not just a defective thermostat/gauge).

Why it overheated I don't know, but it probably did and damaged the head gasket. My repeated attempts to start the engine and run it as much as I could probably didn't help, and maybe the carburetor also got either clogged or damaged by the overheating? So when I finally replaced the head gasket / thermostat/ etc. , it still didn't start, but I do think it was necessary (this gasket was blown clearly, and it matches the overheating issue). Now with the carburetors, I probably had really bad luck (trying 3 of them, none worked...really??) but also I tried them before replacing the head gasket, so this might explain that.
Now, it starts, but still overheats, which means that if I don't want to start it all over again, I'd better find out why. I am going to follow Don's owner's manual little diagram on overheating troubleshooting starting tomorrow. I do have a good water flow both in and out... I took the water pump out despite the good water flow, because I figured a cleaning and a new impeller couldn't hurt at this point (and I thought that maybe the flow used to be better, once upon a time, and maybe my impeller was worn out... which it wasn't. But anyways).

The path to go sailing is a little closer but still far away. Thanks for your help and support, I was really really desperate, and I still can't believe the miracle that happened today. It's like it was waiting for me to be at my lowest before giving me a little hope and keep me going a little longer. This engine is sadistic.

[JOHN COOKSON]

A Couple Of Ideas

From what you have posted I'm not convinced you are really overheating.
Get yourself one of those fancy infrared thermometers and find out what is really going on temp wise.
Run a temporary jumper wire from the sending unit to the gauge. Any grounding of the wire sending unit->gauge will give a false high reading. Are you sure the sending unit is matched to the gauge? You can check the gauge as follows: Disconnect the wire from the sending unit at the gauge. Power up the gauge. It should peg low. Next take a short wire and connect the sending unit terminal of the gauge to ground. When you power up the gauge it should peg high. Don't leave the gauge powered up for more than a minute or two when the engine isn't running because when you power up the gauge you are also powering up the coil.

TRUE GRIT

[JOHN COOKSON]

I missed it last night.
Ditch the thermostat and clamp the bypass hose and report back.
We'll find out once and for all what is going on here.

TRUE GRIT

[Dave Neptune]

Did you show good water flow out the back? If not remove the exit fitting on the manifold and look as well as poke around in there a bit. It is a notorious spot for bits of rust etc to gather and clog the flow.

When/if you remove the t'stat take a good look at what you can see, it just may be time to give her a flush.

The overheating probably is what killed the head gasket if it is overheating so do check the gage or get an infrared temp gun and check~ther pretty cheap now or perhaps someone you know has one you can use. The gun shot at the sender should confirm gage performance if you can't get part numbers.

Good she lit for you, don't change a thing other than playing with the cooling system now one thing at a time.

Dave Neptune

[Mo]

Did you show good water flow out the back? If not remove the exit fitting on the manifold and look as well as poke around in there a bit. It is a notorious spot for bits of rust etc to gather and clog the flow.

When/if you remove the t'stat take a good look at what you can see, it just may be time to give her a flush.

The overheating probably is what killed the head gasket if it is overheating so do check the gage or get an infrared temp gun and check~ther pretty cheap now or perhaps someone you know has one you can use. The gun shot at the sender should confirm gage performance if you can't get part numbers.

Good she lit for you, don't change a thing other than playing with the cooling system now one thing at a time.

Dave Neptune

Just noticed this one...asleep at the switch. That should do it Dave...agree 100%.

[Al Schober]

You say you added fresh fuel a month ago. That doesn't mean you're getting fresh fuel to the carb. Keep in mind that the fuel pickup tube doesn't go to the bottom of the tank - they usually end about an inch or so above the bottom. And guess what collects in the bottom of the tank - water (plus other mung). The fuel floats on top of that.
You've got to get a separate line to the bottom of the tank and use a hand pump to pull a gallon into a glass jug (so you can see what's there). In my boat, I can snake a piece of 1/4" PEX tubing through the fuel fill to the bottom of the tank. Last time I had fuel problems, I pumped out a gallon - that was half water. The gas went back into the tank, and the water was otherwise disposed of. Oh yeah, had to replace the o-ring on my fuel fill cap.

[damienk]

Thank you John and Dave for your help! I still have my issue and I think I tried it all or pretty much, so anybody kind enough to read all my troubleshooting experience (of the cooling system) below and give me a suggestion, it will be very much appreciated!

John > I might very well try what you said, if not to check if I'm really overheating, at least to check if my gauge is working properly. However, I am weary of doing anything electrical, that's really my weak, weak point. And also, I do get other overheating indications, like smoke (white smoke on the outside exhaust) and sometimes a very high engine temperature (it is really burning to the touch). However, some other times, it is all cooled down but the gauge still reads high. The gauge reading is moving, so it doesn't look like it is stuck in high, it does fluctuate.

Dave > I agree 100% and I followed your advice yesterday. In fact, I grabbed my copy of Don's manual and followed his "faulty tree for overheating raw water cooled late model atomic 4". I was so happy to have a clear guideline to follow, BUT...
I did everything he recommended. EVERYTHING. And it still overheats.
I do get a very good water flow on the outside of the boat, so Don's guideline says "clamp off the bypass hose". This got me very, very confused, as if I disconnect the bypass hose, water flows everywhere in the engine compartment like crazy. So I am not sure I have the cooling system configured the way Don thinks I do. My bypass hose connects on one end to a "T" fitting (connected on the 2 other sides to the water jacket side plate, and to the water pump output, where the cool water comes in). So disconnecting it just means the cooling water goes in my engine compartment without even getting inside the engine.
On the other end, the bypass hose connects to the Thermostat housing. If I disconnect this end, and I prevent the cool water from exiting from the bypass hose, eventually I get water flowing in (hot) from the thermostat housing.
None of this seems to reduce the temperature.
So as I said, I am not sure I have the same configuration as in Don's faulty tree troubleshooting, but in doubt, I went both ways on the tree:
One recommendation was: check the thermostat, make sure it works. In my case, this thermostat was removed together with the housing when I replaced the head gasket, and clean thoroughly, and tested in hot water. It looks brand new, so does the housing, and it opens smoothly (in hot water at least). I did remove it again while troubleshooting after the engine was really hot and it was in open position still. So I'd say it works fine.
The other recommendation of Don is to flush the head and block and to clean the side jacket plate. The head, since I just reinstalled it, is clean as a whistle. I soaked the thing for days in vinegar, cleaned it with air compressor... it is as clean as new. The block, I didn't remove it, but I cleaned all I could with it being in the boat, and I did remove all the junk I could from the water jackets. Yesterday, I removed the side plate, cleaned it well, removed and flushed all the junk inside, then put it back. AND, I did an acid flush of the head and block. I had a lot of trouble flushing it (as my engine overheats VERY quickly, so I couldn't flush as much/fast as I wished) but I did it.
So basically, I did it all. NO improvement whatsoever. Then I simply removed the thermostat after reading about fellow boaters doing without. I figured that on an old engine and with the hot Florida water, the risk of running too cool was limited. This actually seemed to work for a while, with the temp going immediately and suddenly down to like 150/160. But this victory lasted only about 5 to 8 minutes, after which the gauge decided to just jump back instantly to the max, and it stayed there since then (after many more hours of troubleshooting and trying).

I was so desperate, I decided I would also check my water pump, which I did (inspected, impeller replaced) but it was and is working just fine. And I forgot to mention that during the whole troubleshooting process, I am feeding the engine cool fresh water from a bucket, so I am taking any intake issue out of the equation.

Then I disconnected each hose one at a time and forced water in the cooling system to see if I have a blockage somewhere. I couldn't find any (putting water in at the thermostat housing, it came out well at the manifold exhaust).

So as you can see, I think I tried it pretty much all. So, WWDD in my situation? How can this be? Good flow, good circulation, still overheating? (the block gets very hot, the temp gauge stays all the time at the max, and I get white smoke coming out of the exhaust after a few minutes of running).
Any idea about what I should do next? it doesn't make sense to me.

[damienk]

Today I will take a gun and point it at the temp sending unit to check the temperature. Thanks Dave for telling me where to check it, I had no idea where to use the gun ( on the block? on the manifold?) so that's why I haven't used one until now. To make sure I do it right, what results should I get (should the reading from the sending unit theoretically match the gauge exactly? If my reading is lower, does that mean I am good and can keep the engine running?)

I think I will also try to disconnect the bypass hose and block both ends and run the engine to see if that does anything, I haven't done that yet because I was by myself and I can't both check the temp and block the water with my fingers at the fittings. If this helps at all, I guess the answer is putting a ball valve inside the bypass hose, but I doubt this will help because I pretty much did the exact same thing with the engine off (forcing water into the cooling system) and when I went to start the engine, temp was still maxed out.

[Mo]

Thank you John and Dave for your help! I still have my issue and I think I tried it all or pretty much, so anybody kind enough to read all my troubleshooting experience (of the cooling system) below and give me a suggestion, it will be very much appreciated!

John > I might very well try what you said, if not to check if I'm really overheating, at least to check if my gauge is working properly. However, I am weary of doing anything electrical, that's really my weak, weak point. And also, I do get other overheating indications, like smoke (white smoke on the outside exhaust) and sometimes a very high engine temperature (it is really burning to the touch). However, some other times, it is all cooled down but the gauge still reads high. The gauge reading is moving, so it doesn't look like it is stuck in high, it does fluctuate.

Dave > I agree 100% and I followed your advice yesterday. In fact, I grabbed my copy of Don's manual and followed his "faulty tree for overheating raw water cooled late model atomic 4". I was so happy to have a clear guideline to follow, BUT...
I did everything he recommended. EVERYTHING. And it still overheats.
I do get a very good water flow on the outside of the boat, so Don's guideline says "clamp off the bypass hose". This got me very, very confused, as if I disconnect the bypass hose, water flows everywhere in the engine compartment like crazy. So I am not sure I have the cooling system configured the way Don thinks I do. My bypass hose connects on one end to a "T" fitting (connected on the 2 other sides to the water jacket side plate, and to the water pump output, where the cool water comes in). So disconnecting it just means the cooling water goes in my engine compartment without even getting inside the engine.
On the other end, the bypass hose connects to the Thermostat housing. If I disconnect this end, and I prevent the cool water from exiting from the bypass hose, eventually I get water flowing in (hot) from the thermostat housing.
None of this seems to reduce the temperature.
So as I said, I am not sure I have the same configuration as in Don's faulty tree troubleshooting, but in doubt, I went both ways on the tree:
One recommendation was: check the thermostat, make sure it works. In my case, this thermostat was removed together with the housing when I replaced the head gasket, and clean thoroughly, and tested in hot water. It looks brand new, so does the housing, and it opens smoothly (in hot water at least). I did remove it again while troubleshooting after the engine was really hot and it was in open position still. So I'd say it works fine.
The other recommendation of Don is to flush the head and block and to clean the side jacket plate. The head, since I just reinstalled it, is clean as a whistle. I soaked the thing for days in vinegar, cleaned it with air compressor... it is as clean as new. The block, I didn't remove it, but I cleaned all I could with it being in the boat, and I did remove all the junk I could from the water jackets. Yesterday, I removed the side plate, cleaned it well, removed and flushed all the junk inside, then put it back. AND, I did an acid flush of the head and block. I had a lot of trouble flushing it (as my engine overheats VERY quickly, so I couldn't flush as much/fast as I wished) but I did it.
So basically, I did it all. NO improvement whatsoever. Then I simply removed the thermostat after reading about fellow boaters doing without. I figured that on an old engine and with the hot Florida water, the risk of running too cool was limited. This actually seemed to work for a while, with the temp going immediately and suddenly down to like 150/160. But this victory lasted only about 5 to 8 minutes, after which the gauge decided to just jump back instantly to the max, and it stayed there since then (after many more hours of troubleshooting and trying).

I was so desperate, I decided I would also check my water pump, which I did (inspected, impeller replaced) but it was and is working just fine. And I forgot to mention that during the whole troubleshooting process, I am feeding the engine cool fresh water from a bucket, so I am taking any intake issue out of the equation.

Then I disconnected each hose one at a time and forced water in the cooling system to see if I have a blockage somewhere. I couldn't find any (putting water in at the thermostat housing, it came out well at the manifold exhaust).

So as you can see, I think I tried it pretty much all. So, WWDD in my situation? How can this be? Good flow, good circulation, still overheating? (the block gets very hot, the temp gauge stays all the time at the max, and I get white smoke coming out of the exhaust after a few minutes of running).
Any idea about what I should do next? it doesn't make sense to me.

When you took the hose off the manifold you needed to remove the one from the rear (depending on engine orientatioin) that goes to the hot exhaust. That hose should be pumping full bore...just driving water. It will come out the top of the manifold and go directly to the hot exhaust. Also have a look for a valve on the exhaust (just after the manifold)...sometime people put them in ...since you are a newer owner it's worth a look. Also, clean that port on the end of the manifold...ensure there is not a flake of rust being pushed up and blocking flow.

Now pull the plugs and see if there are any "droplets" on the plugs. Wet looking plugs smelling like gas, is gas. A droplet is water on the plug. They might look clean as well, depending.

Now, check you oil and see if it is greyish, foaming or water bubbles on the dip stick. If so, the head comes off again and look for signs where water went past. Compression is the same on two cylinders...the others, with normal numbers, likely predict the true condition of the rings. Look closely at the block for a crack and ensure the block and head are shiney clean. You will be looking for signs of water bypassing on the head gasket and or a crack between the two cylinders.

Try that exhaust and ensure water out the stern. But, before you venture with the head, take a few pics of your hose routing system, exhaust system and a short video of the output of water so we can have a look. You can upload your video on youtube and imbed it in your next post.

I know you are having a hard time with this but hang in there.

[Dave Neptune]

damienk, to pinch off the bypass hose is not to remove it! Literally take a "C-clamp" or "vice-grip" type pliers and "PINCH" the bypass hose to restrict the water "FLOWING" in it. This will force ALL of the water THROUGH the engine and should drop the temp considerably. If not time for a flush, I suggest vinegar first if you do.

Did you check under the fitting at the end of the manifold?

Dave Neptune

[Mo]

Now, check you oil and see if it is greyish, foaming or water bubbles on the dip stick. If so, the head comes off again and look for signs where water went past. Compression is the same on two cylinders...the others, with normal numbers, likely predict the true condition of the rings. Look closely at the block for a crack and ensure the block and head are shiney clean. You will be looking for signs of water bypassing on the head gasket and or a crack between the two cylinders.

Regarding my previous post: Lets back up a second. You have decreased compression on two adjacent cylinders. Steam out the exhaust with flow, no start situation....it's worth a pressure test on the exhaust manifold as well. If not resolved before having to remove the head again I'd be pressure testing the exhaust manifold.

My reasoning is that you have two cylinders with poor compression on both mid cylinders, steam out the exhaust, starts only with ether....I would rule out a fracture in the manifold. The crack could possibley be an exit for compression, allow water into the combustion chamber and put out the fire. I'm thinking, once flow is confirmed, this could be an avenue.

My gut feeling is that the issue is there with those two low cylinder compression indications...head gasket, crack, crack or rusted separator in manifold.

But I agree, check the flow first.

[damienk]

MO>> it might be confusing because I initiated this thread with a non-starting engine but it is now running (was a combination of bad carb and blown head gasket): the issue I have now is the engine overheating. It is otherwise running very smoothly. You were right about the head gasket / rust in the manifold but now both the head and the manifold are clean and good.

DAVE >> Lol. It must be a mix between English not being my first language and being a poor mechanic. Thanks for clarifying! I am going to clamp this thing properly right now and see what happens.

Did you check under the fitting at the end of the manifold?

What do you mean? I am doing my best but you should keep in mind that I am a much worse mechanic than I seem to be. What should I check / look for, and which fitting is the one "at the end" of the manifold ? I think I have 4 fittings on my manifold:
- 1 is a very small and key-like looking fitting (sort of a "T"), almost looks like it is supposed to spin or like a valve, it is on the main side of the manifold and I have no idea what it is and actually wouldn't mind finding out.
- 1 is a hose fitting, on the top on the same end as the thermostat housing. I believe it is part of the cooling system (it goes to my water heater, which is connected to the thermostat housing, and on pictures of other engines I saw it directly connected to the thermostat housing).
- 1 is another hose fitting, on the top on the exhaust side of the manifold. It is also part of the cooling system and it is where water exits the engine into the exhaust pipe I think.
- 1 is a larger hole, on the back side of the manifold. It connects directly to a large, non-flexible, aluminum looking duct that I believe is the exhaust.

Which one of those fitting are you talking about, and what should I look for under it?