• If you log in, the ads disappear in the forum and gallery. If you need help logging in or getting registered, send request to: webmaster@southernairboat.com

Idling Problem

FrogNutz

FrogNutz

Well-known member
I need some advise.

I have an 0540 angle valve engine, with fuel injection, that won't idle worth a crap after it gets heated up. It runs great when my foot is on the throttle, and will idle fine when the engine is still cool-ish. But, when I'm trying to idle back down the canal after a long ride it spits and sputters, and makes a loud, intermittent ticking sound. I've tried shutting off one magneto at a time when it's doing it, but it makes no difference.

My buddy told me that I need to have my flow divider rebuilt. (or "spider valve" as he calls it) I know my plug wires are getting to the point of needing to be replaced. But, I'm pretty sure that's not the problem, because I don't see any arcing when it's doing it in the dark. (just PM'd Mike Thurman for a new set, just in case)

I'll be home on leave soon, and I really don't wanna have my boat out of commission for the two weeks that I'm there. Any suggestions?
 
Make sure your injectors are clean. Take them out and soak them in Hoppe's #9 gun solvent.(I had an aircraft guy mechanic tell me how to do this). It makes a huge difference if they are clean. By cleaning them you take them out of the equation. As for taking the divider apart, there ain't nothing to that either. make sure the pinhole is open on the top cover plate(it has a diaphragm inside). Mine had some corrosion in it but was easily cleaned up.
 
I tried the lean and rich and it didn't seem to help much.

I might just try pulling that divider apart and cleaning it. You say it's not complicated? I can screw up an anvil with a feather duster!

Wouldn't it run bad cold or hot if the injectors were dirty?
 
When your motor heats up it expands. Could be you have some sort of cylinder leakage. Around the intake gasket or a cylinder is separating.
 
..CHECK VALVE CLEARANCE.

You say when it's in the lower temp it's fine but after a power run or upper temp it idles badly.

it may be your valve clearance. i've been there, with this problem before. you see, if engine is still cold, the valve stems are not yet stretched due to temperature so you have your cylinder well sealed. when the stems stretch, this is where the clearance comes into play. at idle, the lost of compression due to stretched valve stems is more critical than in throttled operation. at idle, the leak reduces compression dramatically beacase there is more time for the air to escape while at higher rpm, the loss is somewhat lessened and perhaps negligible.

valve clearance should be checked on a maintenace schedule specially if you have new valves. new valves tend to stretch and settle to a final length first before you can get a consistent clearance check period. on the other hand, if you already have old or worn valves, those too tend to stretch after a certain service period thus requiring more frequent clearance check and up to a point they need to be replaced when they are stretched... don't wait until they break.
 
oh, there's a ticking sound and loud? quit running the engine. open the valve cover and check the valves and rockers. it may be on the valve train and maybe something is about to break!!!
 
Thanks for the advise guys.

As much as I hate to go without my boat while I'm home, it sounds like I'd better get it to a mechanic.

Not really what I wanted to hear, but sounds like words of wisdom. Thanks. :(
 
propblast26":1zg9qwo7 said:
..CHECK VALVE CLEARANCE.
.
Click to expand...

This is where I'd start.

Heck of note to have to work on your boat when you get home on leave, though!

Stay safe, man!
 
Might just be the magneto impulse making the clicking sound. The only time you can hear it is at idle. Both of my airplanes and airboat make the same sound at a very low idle speed, 500 to 650 RPM.
Gerry
 
You must log in or register to reply here.
Back
Top