Rough Idle "82" 115hp Evenrude

arrow62

Cadet
Joined
Apr 12, 2006
Messages
22
Okay guys, I'm trying to figure out why I have a rough idle on this motor.
I've checked the gap on the plugs, Compresion is about 120 on each cylinder on the starboard bank and runs around 100 on the port bank. I've also rebuilt the carbs and the fuel pump. I've completed most of the test on the ignition that my manual has. The one test I was curious about is the Charge output coil test. According to the manual I should get a minimum voltage output of 150 volts. When I checked mine, the voltage was 115 volts AC. It says I should change the charge coil if the value is less then 150. Asking for opinions?
Also, where the trottle and shift linkage connect to the motor there is a lot (about 1/2") of slop starboard to port, Should there be this much slop?

One more thing, under the flywheel, I think it is called the timer base has a lot of what looks like dirty grease and the trottle advance ( I think that is what it is called) seems real slugish. Should this be cleaned?

Currently the motor has a rough idle, When we had the boat out a couple of times this year it seems to run great out of the dock, but then seems like it wants to bog down after it heats up. It is kinda intermittant.
Plenty of water coming out of the pee hole.
Any recomandations?

Thanks
Arrow
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Rough Idle "82" 115hp Evenrude

if you gauge is accurate, the compression on the port bank, is at minimum. clean the throttle plate, should move smoothly. take an induction timing light, with you next time out. connect to battery as usual, then when it starts to bog connect to each individual plug wire and watch for interminent spark or no spark. could be coil failing or power pack. i would do a decarb and see if it will bring the compresssion better in line. look in the engine faq forum. it also could be getting hot, even thought you have a good taletell stream, thermostat may not be opening. you should be able to hold your finger on the top back of the engine between the heads for a 4 count.
 

arrow62

Cadet
Joined
Apr 12, 2006
Messages
22
Re: Rough Idle "82" 115hp Evenrude

The gauge is good, just bought it yesterday. I'm going to de carb it when I get it out on the lake. Sounds like I cannot de carb with the muffs on. By cleaning the trottle plate, does that mean removing the flywheel to get to it?
any thoughts on the charge coil being bad?
Thanks Again,
Arrow
 
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