Still having power issues - Round two

[Oaktown27]

I am back. I started with an overheating problem coupled with a no power problem. I did a tune up, rebuilt the hot riser on the exhaust, new impeller, and raw water valve to diver the cooling water. (thanks to everyone that helped me through that)

The engine starts right up, cooling water is flowing, the engine rev's easily and can be sustained up to 2800 RPM (or higher).

The reverse was not working, so I tightened the reverse clutch. I took it out, and in forward could only get the engine up to 1200-1300 RPM's. It was pushing me, but when I apply more throttle, there is no additional power. I feel like I am at 1/2 power. Tough when motoring into the wind.

I did pull the carb while troubleshooting my first problem. Cleaned it, including the jets. I just finished backing off the adjustments to the reverse clutch, thinking I might of over tightened this and this was the source of the problem.

Nope, still cannot get it over 1200-1300 RPM while in forward. Have looked over the other posts, and since the new riser has a new water inlet, this isn't the problem.

I have checked the advance springs during the tune up. I was thinking of pulling a plug to see if it was sooty, perhaps it is to rich? The only other thought is that the prop is fouled? The water is cold (SF BAY), so not anxious to try to check that.

Any ideas? I am at a loss.......

[joe_db]

1. Suffer the cold and check the prop
2. Check the firing order. If you swap the wrong two wires the engine is still relatively smooth but only has 1/2 the power.

[Dave Neptune]

Joe makes a couple of good points, do check the wires for proper order.

Whenever I have a power loss issue the first thing I check are the plugs. The power comes from the combustion in the cylinders and the plug color/condition can often give a clue as to where to start.

I bought a "Go-Pro" on a stick just for checking the bottom and prop of my boat. I could easily see if the diver was doing a good job or if anything was amiss re growth or something tangled in the prop.

What RPM's did you get before she lost power?

Dave Neptune

[edwardc]

Originally Posted by Oaktown27

… I took it out, and in forward could only get the engine up to 1200-1300 RPM's. It was pushing me, but when I apply more throttle, there is no additional power....

It is my understanding that unless you have an Indego prop, or a 2:1 reduction, this is not unusual for a direct-drive A4.

[joe_db]

Originally Posted by edwardc

It is my understanding that unless you have an Indego prop, or a 2:1 reduction, this is not unusual for a direct-drive A4.

It actually is pretty unusual. That equates to about 5-6 hp. I could get over 2,000 RPM with my old 2-blade and get at least 2400-2500 with my Indigo.

[Easy Rider]

Confirming what Joe says. My sweet spot for cruising is around 1750 rpm but could push 2000 for short bursts and that was with a two blade prop

[Oaktown27]

Thanks, I did check the plugs and the wires.

Wires are in the correct order. Wish it was as simple as that. Also, the plugs looked a little "sooty", so might think this is also a function of pushing the throttle without getting additional power. Thinking more fuel than it can handle.

Dave Neptune, funny thing is my wife said I should get a camera on a stick, and I replied no such thing, so I stand corrected. Thanks. Will look for a cheapy.

In the mean time, I am wondering if a weak spark could be a contributing factor. When I tuned it I replaced the usual, plugs, wires, condenser, Points.

The coil is probably original.

Think I should do this as a potential remedy?


Thanks.

[Dave Neptune]

Check the spark, if it is snappy and a crisp blue traveling 1/4 ~ 1/2" your fine, yellowish and "dusty" replace the coil. Do you have points or an EI ignition? If points it could be the gap or even dirty points. And while your checking give the rotor a twist to be sure the C-advance is functioning smoothly.

Also if you have points how old are they? It can also be a bad condenser giving a weak signal and thusly a poor burn.

Sooty plugs are indicative of an over rich condition. First look to the choke to be sure it is opening completely, an easy check.

Dave Neptune

[joe_db]

A fouled prop will produce the exact symptoms that you have - FYI.

[tenders]

Originally Posted by joe_db

A fouled prop will produce the exact symptoms that you have - FYI.

…and the situation happens so often that I would suggest definitively ruling it out before expending further mental energy on other possible causes! Seems like you’re not sure when the prop was last cleaned. That’s a symptom….

[Oaktown27]

All good advice, going to take a look at the prop and check the choke plate before I do anything else. Will let you all know the outcome.

[Jo Ross]

I'm having very similar issues as of yesterday so I'm anxious to hear if your solutions worked.

Started the engine after a two month sit and a berth shift (towed). Normal warmup with good coolant flow. Got it out into the channel and noticed I had a capped throttle response. Normally I can get very good RMP out of forward gear if I open the throttle. Wouldn't run it that hard for more than a few seconds but this time I had no further response out of the throttle. I forget the max RPMs I was getting but it was low. Eventually the engine started to overheat. I couldn't just sit in the channel with high winds so I ran it out and hoisted sail as soon as possible. Checked spark plugs and fuel filter while out and then just went for it on the inbound. By the time I was near my slip I had basically no power out of the engine and it was hot to the point where I think all of the coolant was steaming off before it made it to the exhaust.
Not super happy about that. I'm going to do some troubleshooting today but any update on your situation would be appreciate.

Cheers.

[joe_db]

Usually any bottom paint on the prop is removed by the time you motor a mile. If I let my boat sit for a month the prop absolutely would be foul.

* my buddy used special zinc prop paint. He launched, motored about a mile down the channel, discovered a bad leak, and turned around to haul back out. The zinc paint was gone

[Dave Neptune]

Jo Ross, sounds like you have two issues, over heating and lack of power.

The lack of water exiting the exhaust was probably due to "flow" causing the over heating not the heating evaporating the water. You will need to check the intake for flow and if it is clear then the pump, block restrictions etc..

The power loss could be many things. Since you pulled the plugs, what color were they. Were they white, sooty or an even brown? Fuel flow (pressure) can really be a big limiting factor as well as bad fuel. How long since your last tune up and what was done?

A dirty prop can really cause a loss of power and RPM's but should not cause a heating issue as with low power there is not much heat to dissipate and a hot engine can also loose power as it begins the seize .

Dave Neptune

[W2ET]

Have we done a thread on all the interesting things applied to props to keep them clean?

Bill

[Jo Ross]

Originally Posted by Dave Neptune

Jo Ross, sounds like you have two issues, over heating and lack of power.

The lack of water exiting the exhaust was probably due to "flow" causing the over heating not the heating evaporating the water. You will need to check the intake for flow and if it is clear then the pump, block restrictions etc..

The power loss could be many things. Since you pulled the plugs, what color were they. Were they white, sooty or an even brown? Fuel flow (pressure) can really be a big limiting factor as well as bad fuel. How long since your last tune up and what was done?

A dirty prop can really cause a loss of power and RPM's but should not cause a heating issue as with low power there is not much heat to dissipate and a hot engine can also loose power as it begins the seize .

Dave Neptune

Dave, I think you're 100% right after I did some more tinkering. Looks like the cap to my coolant pump is hemorrhaging coolant and needs a new gasket. I'll verify the impeller once I'm in there also. That has to be the coolant issue. I'll hit the carburetor with cleaner and double check compression today but the spark plugs looked as clean as when I put them in there when I pulled them out.
Also have a diver coming to clean the bottom and check the prop for fouling.

Can marine growth cause a "fouled prop"? I thought that was just fishing net or lines that could wrap a prop.

Thanks for the reponse!

[Dave Neptune]

Barnacles and crustations can cause big issues as they create drag as well as a disturbance to the water flowing over the prop. This creates both drag and cavitation increasing the load on the engine and not transferring the power to the water which drives the boat.

Re the cover if it leaks it also "sucks" air so the water is not moving through the pump efficiently at an approximate 700:1 ratio which is the air to water density ratio. IE the pump sucks air and not very much water with even a minor leak.

Cleaning the outside of the carb does little to clean the innards which also need a good blast of air to actually clean. Before cleaning the carb check fuel flow IE the filters. The only real check for fuel delivery is a "cheap" pressure gage. If the plugs had little color or were white it does indicate a lean condition and unless you know the carb is getting enough pressure cleaning is possibly a waste of time. A good color for plugs is light brown to brown. Dark brown to black is to rich.

Dave Neptune

[Oaktown27]

OK, I am back as I was waiting to to get the hull scraped and prop cleaned.

Went over yesterday, and the motor started right up, but unfortunately the power issue still exists. I did check the choke plate is wide open and the spark arrestor on the intake is clean.

When I did pull the plugs before, they were a bit black, which I think suggests to rich. I assume this would be a carb adjustment, but when there is no load the engine responds and powers up.

Could the stuffing box contribute to this?

Sort of at a loss, and am headed out on Thursday at 1/2 power.

Pete

[Dave Neptune]

If it is just an idle adjustment try opening the "idle air" screw a half of a turn to lean the idle. This is all that is adjustable. If it running rich beyond idle it is a problem inside the carb like a plugged air jet or float level to high.

A poor tune can also cause dark colored plugs. Have you checked for a good spark? Does the C-advance move freely? And have you moved the distributor which changes the timing and can also contribute to plug color.

Dave Neptune

[joe_db]

Do not tune anything until you check the prop though.

[Oaktown27]

Prop was cleaned during the hull cleaning last week. Interesting development yesterday. Looked at the distributor again to make sure the mechanical advance was free to move (is free and functioning), so adjusted the timing a bit both ways to see if there was a difference (there wasn't).

While I was testing in gear I had it maxed at ~1400 rpm, when it would suddenly jump to 2000 rpm. Prop and drive still turning. When I throttled back and tried to accelerate it would go above 1400. This happened several times.

Based on this I am now thinking the fuel system is the culprit. I know I thought it was running rich, so pulled a spark plug. Looking at this again, it is not terribly sooty.

Attached photo.

[Dave Neptune]

That is an extremely lean condition. The porcelain ( the white ceramic around the electrode) is what you "read" and no color means almost no fuel. The black on the edges of the body of the plug is not indicative of much of anything especially in a poor running engine. If you run it again try engaging the choke slowly while the engine is struggling in gear against the dock lines. If the engine speeds up for a few seconds check fuel pressure or delivery. Could be as simple as a clogged filter or a leak in the fuel line sucking air. A cheap pressure gage will save a lot of fussing around and gathering very little actual info. Do check the fuel connections to be sure they are not sucking air.

Dave Neptune

[Oaktown27]

Back at it, and installed a fuel pressure gage and checked for air leaks. Fuel pressure is a constant 3 psi (not under load).

I did take out the Gypsy Rose last week, and still couldn't get it above 1300 RPM, but was still moving.

In summary
Prop/Bottom scrapped/cleaned
Cleaned carb
Fuel pressure gauge and polishing filter
Fire order correct, and mechanical advance free to move
New plugs/points/coil

Guess maybe I just have to live with it. The only other thing I could think of is to rebuild the carb.

[Dave Neptune]

Two questions.

#1 Are your plugs still white?

#2 What are you doing when you "clean" the carb?

Rebuilding the carb is essentially disassembling cleaning and checking the float setting then putting it back together with a new gasket. The needle and seat is seldom replaced unless it is leaking and replacing the shaft seals should only be done by a pro or very skilled carb mechanic. This is what lead me to question #2.

Dave Neptune

[capnward]

It would be good if we were more specific about what is involved in cleaning or rebuilding the carb, and what the difference is. We A4 owners eventually become skilled in doing this. It should be expected as part of maintenance. I disassemble the carb every spring, clean it and remove the idle jet and maybe other jets, run a small wire around in the idle jet to remove any unnoticeable obstruction, put a bigger wire into the idle ports, check the spacing of the float, dress the float valve seat, and reinstall with new gaskets. I replace filters at the same time. I just call this cleaning the carb. Before I stopped using ethanol fuel I would get brown goo in the carb, requiring this annually if not oftener. Since then, I do it to be proactive, as dirty fuel is in my experience the commonest issue with these engines. To me, rebuilding the carb would be to do the above plus replace the jets, valves and nozzles with new ones. Usually not necessary.