Evinrude 135 1975 Idle setup

stuie1982

Cadet
Joined
Oct 9, 2013
Messages
10
Hello,

To cut a long story short I rebuilt an Evinrude 135 and gave it new rings, gaskets and full electrics. After the rebuild, it ran very erratic and after running it with the garage lights off I could see clear HT leaks from all 4 of the new HT leads at the spark plug so I replaced them all with the old ones and it now runs much better (with no HT leaks) apart from the fact it has a rough idle and if you leave it for 2-3 mins it will cut out and you can start it again fine. Timing is 100% ok as I checked like 3 times during troubleshooting. Compression is excellent.

While it was idling I adjusted the idle screw and it seems to get to a point where it suddenly starts running much slower(where as above it will eventually misfire and cut out), if I made a few turns back it would jump back into life (and run forever) so my question is what is it effects the idle speed - is it just the timing (screw I was adjusting) or do I need to do something with the linkage? Maybe there is idle jets in the carbs? Really not sure about it and could not find anything on google.

I have followed guides online to setup the linkage and as far as I can see have done it right buts it's an old linkage.

Would much like any advice. I'm so close to having a beast of a engine!

Thanks
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: Evinrude 135 1975 Idle setup

You didn't list a model number, I just looked at the first model listed.
It does not show any idle mixture screws, just fixed orifices. Have you had the carbs apart and cleaned the orifices?
It sounds like you are running it on a hose, if so you wount be able to set the idle properly. You need to have the boat in the water and the engine warmed up and in gear. With no back pressure on the exhaust, the engine will run different than if in the water.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: Evinrude 135 1975 Idle setup

The jets on the carbs are fixed. When the engine idles, both butterflys are to be completely closed. There must be no carb cam pressure on the roller. You need to check this with the airbox cover off. The carb throttle linkage between both butterflys is adjustable with a screw fasterner between the two ends. It is possible for one carb butterfly set to be closed and the other to be just slightly open. This will cause idle problems if not adjusted properly. The engine will draw enough air through the holes in the butterflys to permit normal idle. The idle itself is determined by the idle spark advance, not by any carb setting. To set the normal idle, float the boat in the lake, start the engine and shift into forward. Turn the large screw on the spark advance lever till the engine idles between 650 and 700. You can't set idle on the trailer. Don't worry about the idle timing degrees, set it to the correct rpm as yours will be unique to your boat, prop pitch and how deep the exhaust is underwater at idle.
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,129
Re: Evinrude 135 1975 Idle setup

Sounds like you rebuilt an engine without looking into the carbs.
You should take them all apart and clean them up, last thing you want is a carb running lean on such a nice cleaned up engine
 
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