Running rough

[skiboarder]

Well I have tryed just about everything. My epic21 has been running rough in idle all season so far, I have tryed new fuel filter, plugs, new gas, check maf and checked pcv valve. What els could it be? Could it be my timming? help me!!!

[Capt Rick]

What is the idel set at
pull 1 coil pack connector one at time to see if each cylinder drops in rpm when pulled.

[skiboarder]

I have tryed the coil pulls and every cylinder droped rpms and ran bad. I dont think its the coils.
I am not in front of it but i think the idle is at 700-800 rpms. When I say its running rough, the rpms are going up and down like from 700-1000 up and down. It runs good when you gun it and wot is 5800 rpms @ 50mph.

[jeffcpa]

Did you use Stabil or some other fuel additive for the winter ?

[skiboarder]

I used stabill for the winter and I have long used that gas up it does it even after fresh premium fuel. I have never used cheap gas. I did try fuel injector cleaner in my last tank of gas felt no diferent. I did here a noise yesterday when I had the motor cover off sounds like a noise from one of the timing pulleys could the timing be off a little?

[Capt Rick]

If the only issue is idle goes up and down that is normal. it caused by the engine sensor the water temp is causing the engine to hunt. does it run fine at all other rpm's

[skiboarder]

Well I think so but that seems strange that the motor is supposed to do that. As far as I can tell its only idle. Thanks capt.

[westtx]

Mine does it too...seems like its more frequent when idling and drifting over boat wakes and swells.

[lesman01]

Yes, mine does that too. It's almost like the idle is not quite set high enough. But my reference is a car engine that stays constant at idle. I get the sensation that it is about to choke out, but it has NEVER died while idling.

Rick, "hunting" is exactly what it feels like. what is it "hunting" for? Wabbits? 

[mplecture]

Any definite answer on this one?

Mine dies at idle. It is OK when first starting up for the day but after it warms up it will die unless I get in gear and get RPM up after initial start up.
 
Runs great with throttle above 1000 RPM

I am going to start with the fuel filter.
 
 

[Capt Rick]

Spark Plugs and fuel pumps working..............     1 st put new plugs in.....

[cyclone]

Make sure that your throttle cable and linkage is working properly, it can make the engine not always return to the same idle speed and do goofy things.

[flyn2001]

My boat does something similar as well.  If I just bring the throttle to idle, it seems to idle smoothly. However, if I reverse then bring the boat to idle, it seems to run sort of rough also (almost like it is smooth then drops rpms then smooth, drops rpms, etc.  When the rpms drop to the low point, sort of a rumble/vibration felt in the boat.  If I push it up past idle then back, it smooths out again.  Kind of wierd....but the boat runs like a swiss watch otherwise.....or a lexus watch (depending on how you look at it )

[skiboarder]

Well I have come to the concusion that maybe my old serp belt is throwing belt dust into the sensors throwing them off causing it to idle rough maybe changing the belt will help this if not I got a brand new belt on and no worries for a while. I just bought one and will change it today and let everyone know what the out come is tonight after we board.

[wakejunky]

Just replacing the belt will not fix it. If that's the problem. You need to clean or replace the MAF sensor. The new belt will keep it from getting dirty, but once its dirty or full of carpet fibers it must be cleaned or replaced. You can spray it out with brake clean, just make sure you mark how it was installed, because it can be installed backwards and it wont run.