79 Evinrude 85 HP stalling at idle and not reaching max rpms

[jbhasaboat]

Hi, i'am new to this forum and was hoping someone could help me with my engine. It's an Evinrude 85hp, i believe the year is 79, the model number is 85999R. i just bought a 1974 17ft Boston whaler Montauk with this engine so im still new to it, this isn't my first boat so i know a little but that was a lot smaller so this boat is a whole new world to me. ok now to the problem, when at idle the engine stalls and runs rough the only way to keep it going is to give it gas but if you do it too fast it quits then once it is running it will only do about 10 mph. i know it should do about 40 mph because when i took it for a test drive the engine ran perfectly and topped out at about 40. Things that i have already done is replaced the gas, checked the plugs, and checked to see butterfly valves are opening all the way which they are. i really don't know where to go from here any help will be appreciated, thanks!

 

[Monte1961]

Re: 79 Evinrude 85 HP stalling at idle and not reaching max rpms

The first thing you will want to do is check the compression. 2nd. Check spark with spark tester(All Plug Wires). A few notes. How long since last tune up? Was the carb/s rebuilt in the last year? Post back results and good luck. Welcome to iboats Monte.

 

[jbhasaboat]

Re: 79 Evinrude 85 HP stalling at idle and not reaching max rpms

ok sorry it took so long to get back to you but i found the problem! the right side of the engine doesn't have any spark, i have changed the plugs and it made no difference. so the question now is how do i go about fixing this?