Idle problems

[bmstang]

I have a 1978 235hp evinrude . I can't for the life of me get the idle to come down. It all started when i changed the plugs. I retarded the timing as far as it would go back performed sync and link did everything. The best i could get the idle to go down to was 1100rpm in neutral motor is in the water. The power pack went out on one side put on a new one and now the idle won't go below 1800 rpm. I finally gave up and called a mechanic he told me there is a vacume leak somewhere. I changed all the gaskets related to the carbs no help . The mechanic came over and said the manifold gasket was leaking he put a new one no help. He said he talked to a rep from evinrude and said the problem was in the power pack even though the serial numbers is a correct replacement they are color coded and both packs have to match or it could result in a high idle. Any help would be appreciated thanks.

 

[mrcj001]

Re: Idle problems

Did you actually retard the timing or did you just try to adjust the idle??

For some reason, the OMC says to check the timing after a power pack service.

Good outboard mechanics are gittin hard to find......

 

[bmstang]

Re: Idle problems

I did actually retard the timing. I moved the throttle arm back as far as it would go which moves the timer base with it. There is a stop that won't let it go back any further. It was set just before 8 degrees where it should be and now i am before tdc.

 

[emdsapmgr]

Re: Idle problems

An unusual situation-for sure. Was the replacement pack a factory (Bombardier) part or aftermarket? Did you contact the supplier of that part for assistance? Would be interesting to know what the idle timing shows on the flywheel. That flywheel should be indexed/marked for timing both the #1 and #2 cyls. (one cylinder from each power pack.) As you idle the engine, does the timing shown on those two cylinders differer between the two? High idles can also be due to one of the carb butterflys being slightly open. Make sure those butterflys on all 3 carbs are absolutely closed at idle-you'll have to pull the airbox cover to do this visual inspection.