Engine starts, but has no power in gear

[BenCT]

I ran my engine yesterday and today. Yesterday in neutral I noticed that even after the engine ran for a while it would stall out if I didn’t give it at least a 1/4 throttle.

Today I tried to motor somewhere and once I put the engine in forward gear I had almost no power. We moved forward slowly and at full throttle the engine was barely moving and ultimately died. I could start it but when I shifted forward engine died. Any thoughts on problems or troubleshooting?

[Dave Neptune]

Sounds like fuel delivery. Could be fuel pump clogged filters or an air leak into the fuel line.
A simple fuel pressure gage mounted just before the carb would be a big help.

did you try applying the choke to see if it helped any?

What kind of fuel pump are you using? And what type of filter(s)?

Dave Neptune

[BenCT]

The pump is an electronic sea choice fuel pump.

[BenCT]

Fuel filter setup

[zellerj]

Symptoms also suggests a clogged air filter or a plugged exhaust. As Dave said, probably a fuel delivery issue, but also could be air flow issue.

[joe_db]

Or........a clogged idle jet. I have had that happen, you had to give the engine enough throttle to get on the main jet.
Repeat advice #1,000: Get a fuel pressure gauge or you are guessing.

[sastanley]

Fuel pressure gauge will at least tell you if the carb is getting adequate fuel delivery/pressure. i just posted this in another thread...I have (had) the Mr. Gasket #1561, but anything similar would work. You want the gauge just before the carb inlet to read the pressure the pump is sending into the carb..about 3 PSI or so, depending on what that Facet fuel pump is producing.

edit - +1 one what Jim Zeller said too...a plugged exhaust (usually right where the water is injected) can also produce the lack of power symptoms. Mine always rusted out and required replacement before it got plugged.

[mhinnc]

If a fuel flow meter shows low but otherwise all else looks normal, you may want to check for a restricted flow at the fuel cut off valve (if one exists) at the tank.

I was having the stalling issue at low to idle throttle. This had been the condition since buying the 50 year old boat two years ago. I cleaned the carb jets, had the fuel tank professionally cleaned, fuel line replace and added a water separating fuel filter. The low idle problem persisted. I finally removed the brass cut off valve and was surprised at the amount of crud that had built up inside. After cleaning out the debris the motor idles fine now.

[BenCT]

The spark plugs were all black on the bottom. Guess it’s called, fouled plugs? Well after replacing the plugs that seemed to do the trick. Fuel looked good. Was getting enough fuel. Oil fine. Replaced plugs and It ran well after that. I think I’m going to electronic ignition this winter. Seems like an inexpensive way to cut down on a bunch of issues. Not sure if it will prevent sparks from getting fouled. The spark plugs lasted all season. How long should spark plugs last?

Also thanks for all the input.

[Dave Neptune]

Plugs should last well over a season. I changed mine every few years as I had a good running engine and even then I noticed very little difference. Old plugs should look the same as fresh plugs as far as color goes however the electrode inside the ceramic center will show signs of wear by being rounded off and not a sharp cut off rod like they are when new. The black is trying to tell you that the engine is not really running "good" just running. Black usually indicates to much fuel (carb), excessive back pressure (plugged up old exhaust), faulty choke not opening fully or a clogged spark arrestor.

A weak spark can contribute to sooty plugs too. Make the change to EI the second best thing you can do for the A-4 but before you do check to get a good look at the spark you are getting now. It should be blue and rather snappy. If it is yellowish and a bit of flash around it it is weak. Get the EI on her and check the plugs after a few hours running if they are again sooty it will be time to look at other things ONE STEP AT A TIME.

Dave Neptune

[Al Schober]

Hey Ben,
Those plugs look oily to me. I'm curious to know if the engine has any other issues such as smoke from the slash tube or flywheel cover?
The lower piston ring is for oil control and tends to wear faster than the upper two rings. You can have good compression at the same time you have oil bypassing into the combustion chamber.

[hanleyclifford]

Have a look at the prop.

[joe_db]

Warning - you can mask a lot of issues with EI for a time, but they will be back. Your plugs should not be fouled, mine can go several years with no issues.

[sastanley]

I agree with most everyone else. One step at a time and get it running better first. EI won't solve any issues.

[ED.D]

On numerous occasions I have had the same problem, being fat, dumb, and happy I always wait until it happens to adjust the idle jet. So far it has fixed it every time over the 22 years I have owned the boat and engine.