Runs good in river idles very high on muffs

[Joe Fisherman]

89 60 hp johnny.My motor runs great when i take it out fishing or boating but when i come home and flush it on the muffs it idles very fast. When i am on the river it doest seem to idle fast it idles just right. What should be done to correct the problem???<br /><br />Last month i idle it down to sound good on the muffs (idle screw) but when i got to the river it barely stayed running and after about 10 min of wot the motorshut down and started a slight knocking noise.I idled it back up and it ran perfect....

 

[rodbolt]

Re: Runs good in river idles very high on muffs

hello read your post and I have fought this one many times on late 80's and up OMC. are these carbs fixed idle air? it sounds like you may be running slightly rich at idle and the lack of back pressure out of the water allows it to breathe easier so it will idle faster on the flusher. this is really common so it may or may not show an actuall problem. if the motor runs fine otherwise I dont think I would chase it much further. most of the 2 and 3 cyl late model J/E carbs were designed to run with the throttle plates compleatly closed. you may double check all your linkage adjustments first. good luck

 

[JB]

Re: Runs good in river idles very high on muffs

It isn't a problem, Joe. <br /><br />It is normal for an engine with zero exhaust back pressure to idle faster than when in the water.<br /><br />That's why the correct "idle" adjustment is done in the water. It affects mixture at all throttle settings.<br /><br />If you want to buy a "flush muffler" to provide back pressure (and quieting) you can probably do your adjustments on the muffs.<br /><br />Good luck.

 

[Joe Fisherman]

Re: Runs good in river idles very high on muffs

Thanks for the advice I just dont feel comfortable running it long on the muffs 20-30 seconds at the most.

 

[Solittle]

Re: Runs good in river idles very high on muffs

Joe - You can run on the muffs for as long as you have fuel without hurting your motor.

 

[G DANE]

Re: Runs good in river idles very high on muffs

Wait a second Joe<br /><br />If your motor has a problem of a kind and you ( or someone else ) turned up the iddle so it iddles with butterflies slightly open, it can "run away" on muffs. That is not good. Here we are talking about maybee 5000 rpm or so. If that is the case, sont run on muffs untill you corrected the problem. Check that throttle butterflies are totally cloused at iddle. Running maybee 1500 rpm at iddle on muffs wont hurt.

 

[walleyehed]

Re: Runs good in river idles very high on muffs

Ditto on the above.......2000 rpm is max allowable, no-load. If it's just a few hundred rpm higher than normal with the muffs, refer to JB's post.

 

[Luna Sea]

Re: Runs good in river idles very high on muffs

Joe,<br /><br />Lose the "muffs" and get yourself a plastic barrel for running the engine in. There's been quite a few posts on here about customizing barrels for flushing. Much quieter too!