erratic engine performance

[rgarrison@gmail.com]

I recently did some work on my engine, new fuel lines, filters, head gasket, etc. Also flushed the fuel tank and filled with new fuel.

Here is my problem, when leaving my slip and upon initial operation of the engine (I go out 3-4 times per week), my Atomic 4 runs and idles great, better than ever.

After sailing for a couple of hrs, I crank "er up and she runs and idles rough. Actually, she has trouble idling below 1200 rpm.

Anybody have this problem? I am assuming part of the problem could be related to junk still in my tank that gets stirred up when we sail (10-15 knots at every tack).

Thanks for any help!

 

[celticwinds]

I would suggest installing a fuel filter with a clear housing that would enable you to see the fuel. Racor makes such a filter. Change the spark plugs first because they may have become fouled and won`t cost much to change. Worst case scenario if she does not want to idle a cleaning of the carb may be in order. Are the points in good condition? Check the spark plugs for fouling , the float in the carb could be sticking and made worse when the boat heels. Check the plugs first.

 

[kloudie1]

Check valve clearances if it has not been done in a few years. Too tight can do that as the engine warms up.

 

[celticwinds]

If the engine runs rough after it is warm check the spark plugs for moisture. Moisture would indicate a cracked intake manifold. I did a repair on an atomic four for a friend and the engine would run like crap after it warmed up because of a bad manifold.

 

[rgarrison@gmail.com]

Thanks, everyone. I'll be at the boat tomorrow and w/a (will advise). I appreciate your input very much!

 

[rgarrison@gmail.com]

I would suggest installing a fuel filter with a clear housing that would enable you to see the fuel. Racor makes such a filter. Change the spark plugs first because they may have become fouled and won`t cost much to change. Worst case scenario if she does not want to idle a cleaning of the carb may be in order. Are the points in good condition? Check the spark plugs for fouling , the float in the carb could be sticking and made worse when the boat heels. Check the plugs first.

funny thing is it will idle like a champ in the slip before we take er out, takes about 30 min. to get the sails up and to big water with the engine running the whole time. Turn er off, sail, and lots of healing. Come back to our marina, crank the engine, starts up okay but about 10 minutes out, she starts idling bad. Total engine time in the RT is about 45 min. Engine temp good ~150.
Oil pressure good.

 

[Nahart51]

You may want to try Moyermarine.com. They have a forum that is really helpful for Atomic Four owners. Don Moyer is the guru of Atomic Four.

 

[rgarrison@gmail.com]

Thanks, i am efforting that but am having troubles with their website.

How are things in Louisiana? I lived in Miss. for yrs, Jackson and Pass Christian.

Again, thanks, Randy

 

[jrowan]

You have done a lot of work to your engine, so it could be a number of different things causing your problem. If you replaced your head gasket, I'm assuming it was cracked from overheating? I assume you torqued the head bolts back to factory specs. during the install.
But if I had to guess, I think that you have a fuel problem. Especially since the engine runs good at initial start up, I would guess that you have some debris still in your tank that is sloshing around under sail. It can then get into the fuel system & cause a partial clog. I had a Yanmar diesel that had a partially clogged fuel lifting pipe in the fuel tank, that would cause my engine to stall out after about 30 minutes. The engine was using the fuel in the fuel filter housing & lines & was then starved for fresh fuel due to the clog. It's an easy thing to check for, just unscrew the fuel pick up tube from the tank & check that it is clear at both ends. I also second contacting Moyer marine though, as they are the gurus of the Atomic 4.

 

[Nahart51]

Hey Randy,


Louisiana is wonderful. Year round sailing as you know. Beautiful brown water, like it's supposed to be. I sail Lake Arthur, swamp sailing. A tack a minute. I know you have to miss Pass Christian.

Dave

 

[Nahart51]

Randy,

I take back you missing Mississippi, just noticed your home port is Dana Point

Dave