wit's end

[damienk]

I have been asked to upload pics, here is one.

From left to right:
1st hose: going from manifold to my heat exchanger / water heater.
2nd hose: coming back from the HE/WH
3rd and 4th hoses: the curved one is the water intake, from the raw water filter to the water pump, the 4th one is the water exhaust out of the manifold.



This is my exhaust system. The hose going up is coming from the manifold, goes up quite high behind the wood panel then down again and connects to the riser (or whatever this aluminum hot pipe is called) right before entering the big white plastic box. Then, another hose goes out of the plastic box, and all the way aft outside the boat.

So, apparently I am not overheating (anymore, because this is probably what messed up my head gasket and fried my gauge and temp sending unit in the first place). I only tried with the by-pass hose clamped, so tomorrow I will try unclamped and see if the temperature rises or not. My gauge reading got me worried but I guess my temp gun is way more accurate (today the gauge did again what it did a couple days ago: it started working again and gave me a normal reading, then with no warnings and in a split second, jumped to max temp. Maybe a bad wiring? it. I will get a new gauge to be safe. I am relieved to hear that the exhaust temperature is within an acceptable range, but the smoke can't be normal. What can it be? It doesn't appear immediately: it starts very lightly after a few minutes of the engine being on, and then keeps increasing in quantity. It is not heavy smoke (you can see through very easily and it can actually be hard to notice it) but eventually it fills up the whole cabin with a very light smokescreen that smells very toxic. It does not start my very sensitive gas fume alarm, so I guess no gas fumes in this smoke. It comes precisely from the connection between the hot pipe and the fitting it is molded, and from the fitting itself (this fitting is connected to the manifold: there is no smoke coming from either the gasket or the manifold it self.
I think there is also some of the same smoke exiting the boat, but it is hard enough to spot inside the engine compartment, outside it gets blown away almost immediately (however, it is a lot of smoke inside, and I'm pretty sure it could do some serious damage to anyone staying inside the boat while the engine is on).
What do you guys think? I was thinking, if it isn't overheating, then maybe a leak or a clog in the riser? But is it normal to get this smoke at all (even exiting the boat)? I can't remember anything like that before (and definitely nothing inside).

I came a long way in a few days thanks to all of you guys. On Monday only, my boat wasn't starting at all. I appreciate the help

[hanleyclifford]

I notice that you are using the most restrictive of fittings. Why not try using straight connections to the manifold or at least cast style plumbers street fittings.

[ndutton]

Your gauge is acting like there's an intermittent short to ground somewhere along the wire.

[damienk]

Everybody > here is a link to a short video, so you can hear the engine running, and see the smoke by yourself. http://www.yourfilelink.com/get.php?fid=1095987


Ndutton > Thanks for the info! However if you want an idea of my electrical skills, I still look at light bulbs like it is magic. I am able to get away with it with logic and usually simply replacing/reproducing an existing system, but fixing a broken one... I will try, have a look at the wires, and see if I see something obvious. If you have a wiring diagram of what it should be like, I am interested, I can follow that. I lately found a few clues that something went wrong with my electrical systems but I am in denial:: my blower stopped working (I found a hot wire in my engine compartment that is linked to the blower switch, but no idea where it was connected before breaking lose) and I found another wire that is hanging lose connected on one end to the top of my coil where a bunch of other wires are also connected. I am pretty sure I never had wires hanging free before. Maybe it happened when I was fighting to remove nuts and bolts and studs all around the engine. But how can I fix something like that? The only way I could do it is with a diagram and checking every wire. Maybe the two free wires are actually meant to be connected to one another? I'm a little afraid to experiment with electricity, I would hate to damage something. Again, a diagram would come handy. But don't even say the word "multimeter" to me, at least not without a detailed step by step and child proof explanation of what to do with it.

Hanley > I will happily switch to better fittings if you can explain me what you are talking about. Maybe a link?

[ndutton]

May I ask where you're located?

This may be an excellent project to start your electrical career. Starting at the temperature sender, follow the single wire, usually tan, to the instrument panel where it connects to the 'S' terminal of the temperature gauge. Carefully inspect the condition of the insulation every inch of the way especially where it might touch anything metallic. Any damage to the insulation should be repaired with electrical tape at least. I won't ask you to replace the entire wire yet.

There are a number of drawings on the forum in their own category for ease of retrieval. Here is the diagram you're looking for.

[damienk]

Thanks! I will try that. It is tan indeed, I remember. I thought it would be a lot more complicated than just one wire from A to B. I think I'd rather replace the whole wire unless that's a bad idea, as it is easier to run a new wire connected to the old one than to inspect the existing one (it goes through very, very hard to access places).
So tomorrow, new gauge wire, and... I don't know what else to do with the exhaust situation.
Anybody knows what the smoke is? or how to check if the hot pipe went bad?

[hanleyclifford]

Is your hot section constructed with galvanized pipe?

[hanleyclifford]

This is the better style fitting.

[hanleyclifford]

If this is a raw water cooled engine that has ben running with a thermostat for any length of time I would operate under the assumption that the block or other castings are at least partially plugged. It is quite possible for an engine to exhibit good water flow and good surface temp readings and yet be overheating in areas of the castings that are plugged. The water simply takes a preferential flow thru the remaining open passages, the surfaces over which can look good. I recommend an acid flush and a change to cast plumber's fittings where practical. Omit the thermostat for now and put a valve on that bypass.

[Administrator]

Looking at the way the red hoses neck down under the hose clamps, it looks to me like there is a size mismatch.

Bill

[hanleyclifford]

Originally Posted by Administrator

Looking at the way the red hoses neck down under the hose clamps, it looks to me like there is a size mismatch.

Bill

I noticed that too. My guess is that the heater core called for 3/4" so that's what was used. The return fitting at the front of the manifold is one of those horrible brass, machined 1/2"NPT to either 1/2" or 5/8" hose. As has been pointed out that plumbing plan is not standard. I think I see the attempt to extract maximum heat from the engine to benefit the heater. This arrangement imposes a burden on the pump especially if this is a raw water cooled engine.

[JOHN COOKSON]

Originally Posted by ndutton

Starting at the temperature sender, follow the single wire, usually tan, to the instrument panel where it connects to the 'S' terminal of the temperature gauge. Carefully inspect the condition of the insulation every inch of the way especially where it might touch anything metallic. Any damage to the insulation should be repaired with electrical tape at least. I won't ask you to replace the entire wire yet..

One ohm meter lead on the center terminal of the sending unit and one on the body of the sending unit. You'll find out real quick if there is a short to ground.
I'm not usually in favor of shotgun parts replacement but in this case it might be easier to skip the diagnostics and buy a new sending unit and gauge and run a new wire between them and be done with it. See post #29.

Part #2:
Get the exhaust unwrapped and see where the leak is.

TRUE GRIT

[HOTFLASH]

In pic (#26) I noticed the teflon tape on what looks like the the temp sender. My understanding is that usually the install instructions say not to use any goop, seal or tape when screwing that into the port in the head, and that doing so can mess up the "sending" function. Maybe that is why the temp gauge is not working.

Mary

[JOHN COOKSON]

Originally Posted by HOTFLASH

In pic (#26) I noticed the teflon tape on what looks like the the temp sender. My understanding is that usually the install instructions say not to use any goop, seal or tape when screwing that into the port in the head, and that doing so can mess up the "sending" function. Maybe that is why the temp gauge is not working.
Mary

One ohm meter lead on the body of the temp sending unit one lead on the head. You'll find out pronto if the sending unit is electrically connected to the head. It may be necessary to poke the probe through any paint or corrosion.

TRUE GRIT

[ndutton]

Originally Posted by hanleyclifford

I notice that you are using the most restrictive of fittings. Why not try using straight connections to the manifold or at least cast style plumbers street fittings.

I propose a cast female elbow with a close nipple to provide the male thread is far and away less restrictive than cast street ells. One look at the opening in the male end of a street ell compared to a close nipple should make it obvious.

Quick calculation after I made some measurements: the I.D. of a ½" close nipple is 0.645" which translates to 0.327 sq. in. cross section. Compare to the I.D. (0.490") and cross section (0.188 sq. in.) of a ½" street ell male end. The street ell has only 58% of the cross section compared to a female ell + close nipple at its greatest restriction.

The only advantage I can see for using a street ell is maybe physical height but it comes at a big hit in terms of flow.

[hanleyclifford]

Originally Posted by ndutton

I propose a cast female elbow with a close nipple to provide the male thread is far and away less restrictive than cast street ells. One look at the opening in the male end of a street ell compared to a close nipple should make it obvious.

Quick calculation after I made some measurements: the I.D. of a ½" close nipple is 0.645" which translates to 0.327 sq. in. cross section. Compare to the I.D. (0.490") and cross section (0.188 sq. in.) of a ½" street ell male end. The street ell has only 58% of the cross section compared to a female ell + close nipple at its greatest restriction.

The only advantage I can see for using a street ell is maybe physical height but it comes at a big hit in terms of flow.

Good observations here by Neil. In selecting fittings for this application I have found over the years that another consideration has to be taken into account - strength. The female plumber's 90 does indeed offer more cross sectional area than the street but requires the use of the yellow brass machined close nipple which becomes the weakest link in the assembly. It is anodic to the 90 and cathodic to the casting both of which relationships set up galvanic cells. In addition the close nipple is physically weak and prone to vibration. On balance the street 90 presents only one galvanic cell and is much stronger physically than the close nipple. I have actually known the brass close nipple to fail in an A4 manifold. Good thing a 1/2" NPT tap was aboard. And one other thing - I always bore out and port the street which substantially reduces the cross sectional difference versus the nipple. If you do use the nipple/female 90 configuration I advise the use of a steel or iron close nipple which still leaves you with one galvanic cell but a lot more strength. Of course, if you go to FWC the problem goes away.

[ndutton]

Here are a couple of hints some members may find helpful:

Originally Posted by hanleyclifford

[the yellow brass machined close nipple] is anodic to the 90 (female elbow) and cathodic to the (manifold) casting both of which relationships set up galvanic cells. If you do use the nipple/female 90 configuration I advise the use of a steel or iron close nipple which still leaves you with one galvanic cell but a lot more strength.

If there's a concern over dissimilar metals or galvanic cell, the normal preventive measure is to install a sacrificial zinc. West Marine carries them in a variety of configurations and sizes, pencil zincs in particular for engine related installations. This is known and accepted as effective protection of dissimilar metals concerns and is exactly why heat exchangers have provisions for zincs.

Originally Posted by hanleyclifford

In addition the close nipple is physically weak and prone to vibration. I have actually known the brass close nipple to fail in an A4 manifold. Good thing a 1/2" NPT tap was aboard.

If there is engine vibration sufficient to damage a brass close nipple, there are bigger problems to resolve than the nipple material. That said, size matters. This discussion is not about the lengthy and therefore fragile 1/8" nipples common on the A-4 for water jacket drains and oil pressure senders.

With the perceived concerns resolved perhaps we can return to flow considerations.

[ndutton]

Damien,
How's it going? We're needing an update.

[Dave Neptune]

d, re the exhaust smoke. If it is coming out from under the "wrap" it can be a couple of things. If the wrap has gotten wet from anything it can take a long time to "boil" off, a very long time! If it is indeed exhaust it should smell like it, so a quick sniff test.

If it persists and does not smell like exhaust I'd peel it off and take a look at the pipe. If it is fresh "galvanized" pipe it will take a while for the galvanizing to "burn" away, this is why black pipe is preferred.

Dave Neptune

[hanleyclifford]

Originally Posted by ndutton

Here are a couple of hints some members may find helpful:
If there's a concern over dissimilar metals or galvanic cell, the normal preventive measure is to install a sacrificial zinc. West Marine carries them in a variety of configurations and sizes, pencil zincs in particular for engine related installations. This is known and accepted as effective protection of dissimilar metals concerns and is exactly why heat exchangers have provisions for zincs.
If there is engine vibration sufficient to damage a brass close nipple, there are bigger problems to resolve than the nipple material. That said, size matters. This discussion is not about the lengthy and therefore fragile 1/8" nipples common on the A-4 for water jacket drains and oil pressure senders.

With the perceived concerns resolved perhaps we can return to flow considerations.

Let me be more specific: A pencil zinc in the block of a RWC A4 will not protect a yellow brass close nipple atop the manifold.

[ndutton]

I think this is really about the practicality of the concern or in other words, is it really an historical problem?

Example: my A-4 was salt water cooled for at least 35 years, never winterized, likely never acid flushed, never had any zinc protection, had the dreaded yellow brass machined elbows in both manifold ports, inlet and outlet.

No problems, no indication there had ever been a problem upon easy disassembly. Sorry but it's undeniable and can't be ignored.

[hanleyclifford]

Originally Posted by ndutton

I think this is really about the practicality of the concern or in other words, is it really an historical problem?

Example: my A-4 was salt water cooled for at least 35 years, never winterized, likely never acid flushed, never had any zinc protection, had the dreaded yellow brass machined elbows in both manifold ports, inlet and outlet.

No problems, no indication there had ever been a problem upon easy disassembly. Sorry but it's undeniable and can't be ignored.

The stock brass elbows furnished in the A4 are not close, but much more robust pipe to barb fittings.

[hanleyclifford]

If you really want to jack up the flow, and get more robust and have better, safer choice of fittings try opening the manifold to 3/4" NPT, easy and plenty of "meat" to work with:

[biohead]

Don't try to light the gas in the parking lot...gas goes boom...even the small amount in the bowl.

Originally Posted by 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.

[damienk]

I have to say I am blown away by the amount of knowledge on this forum. Blown away. you all got it right, and you all have very pertinent remarks. And sorry for being quiet for a couple days I was away from civilization
So yes, the hoses are a mismatch and I understand that the fittings aren't the best but I will hold on those projects until I get my A-bomb running loud and clear.

So right now:

Gauge:
The sending unit is brand new, so I guess it works. I will remove the teflon tape as suggested, and if it works better, I will keep it that way. If it doesn't, I will buy a gauge. Using a ohm meter is way too scary haha.

Overheating:
I did the test with a clamp in the bypass and no overheating. I removed the clamp, no overheating (all checked with heat gun). Thank you all for giving me the range of temperature that I should expect. Apparently, I am now fine with that. I guess that the acid flush, the cleaning of the water plate and the manicure of the head and manifold when I removed them or a combination of all the above somehow worked. yay!

Smoke:
I still have the issue of white smoke coming from the connection between the hot pipe/riser and the manifold. It is hard to tell if it smells like exhaust because I never really put my nose in the exhaust, but it definitely doesn't smell good (a mix of fumes and burnt smell, maybe burnt plastic?). That does bother me a lot, but hey, it runs. But Dave Neptune gave me hope that it might just go away (the riser did get wet inside, so hopefully, it is only boiling off). If not, I will be in the market for a new riser, unless someone else has a better idea?

And... the new problem (if you still have some juice for me lol):
Carburetor issue! I got the engine started using an old carburetor, that is close to being magic: anytime I use this old carburetor, the engine starts right up and purrs as smooth as an happy kitty, BUT I basically completely lose throttle ( I can rev up in neutral, but not in gear. NOT AT ALL). I troubleshooted this issue a long time ago and I know it is the carb fault, because I replaced the carb with another one and it worked perfect, which is why this carb is now my "troubleshooting" old carburetor. However, with the new one, it is not starting AT ALL.
So, I am here at home with 2 carburetors, trying to make a winner out of these 2 losers. I tried combinations of both, and got a rough start with the upper part of the new one (B) and the lower part of the old one (A). Couldn't try the contrary as the screw don't match (they are the same carbs inside, but slightly different outside).
So, anybody knows what to look inside the carb for to solve this throttle problem? I think that with the new one, it is the main jet that is clogged. But with the old one, I don't understand this issue. How is this even possible? I have them both soaking in vinegar right now and hopefully I can get them both to work well. I really don't want to fork $500 for a new carburetor, I already spent a ton of money on this engine lately.

Thanks to all for being so knowledgeable and supporting!