Poor Idling 1996 70hp Evinrude...

[fugi guy]

Hi everone, just purchased my first boat . A 1996 princraft 166 super pro, with a 70 Evinrude. The engine is idling fast and rough, that said once it is off idle runs like a champ. Hot or cold idles the same, and if idles long enuf it will load up and quit. With full throttle it will start again. Changed the plugs , they where [ Champ QL78YC ] is this the correct plugs? They where Black, Run 15 gallons of fresh gas through and still the same..I am going to check the carbs now, and was wondering about settings and specs. Do lots of work on sleds so the carbs shouldnt be big deal [i hope] ..It seems rich to me gas amd oil, can you ajust the oil pump, should i ? Also i turns [RPM] 5400-5500 is this right..Any help and specs for the carbs, or just some input about the over running of this engine would bee great..Thanks in advance.. O ya my elevation is around 500- 1000 ft..Freash water

 

[HybridMX6]

Re: Poor Idling 1996 70hp Evinrude...

Does sound like it's a bit rich. If the carbs are the same or close to it as my '92 60hp, there is an idle screw on the top left side of the carbs (if you are in the boat facing the motor). Manual says to screw them all the way in (lightly seated so as not to damage the needle), then unscrew 1.5 turns. You will need to do final adjustments on the water and when warmed up. If this does not fix the problem, I'd say pull the carbs off and rebuild then with new kits and clean them out real good.
Also, just a side note, there is an electric primer on the engine, should be on the same side as the idle screws. It has a red tab which should be pointed a certain direction, in line with the black cylinder it's attached to I believe. Let us know how it's facing and we can make sure it's correct. it could be just a tad off, letting extra fuel in, which at speed doesn't matter, but at idle could cause a rich condition.

 

[fugi guy]

Re: Poor Idling 1996 70hp Evinrude...

Thanks for the QUICK reply, i did try ajusting the screws you mentioned and did not notice any idling changes?? Actually didnt notice any changes at all. And i did turn the gizmo you mentioned on the same side and the engine quit rate away, but started quickly with some throttle..I think the red pointer is facing the rear of the engine, but i will verify that. And lastly , how does your out board run at low rpms, in gear? Used to working on snowmoblies and a triple sled engine is very smooth.Thanks for all your input, i am thinking a good carb cleaning will help..i will let ya know!

 

[tedious]

Re: Poor Idling 1996 70hp Evinrude...

I've got a 1989 70, and the idle is pretty bad, and it'll quit on you after about 30 seconds of idling. It runs perfectly at speed - sounds pretty much the same as yours. My boat is up in Maine, so I won't be able to work on it until after Labor Day, so I'm just living with it for now. The plan is to rebuild all three carbs - I've already done everything else. The rebuild kits are only about $15 each.

You've already tested the primer circuit, so that can't be the problem - the red pointer should be in line with the solenoid body when running, as you found.

Other things I tried, that I would recommend, are:

- decarb
- link and sync - you'll really need the manual to do this right, but as far as idling goes, you just need to make sure all 3 butterflies are all the way closed at idle. The quick test for that is to loosen the screw that connects the linkage to the upper and lower carbs, and see if the idle improves.

Tim

 

[tashasdaddy]

Re: Poor Idling 1996 70hp Evinrude...

this is the normal primer positions.

 

[fugi guy]

Re: Poor Idling 1996 70hp Evinrude...

Thanks for the info- I am going to do the carbs this week and i will get back to ya ..Is there any way i can get carb section of a manual on-line any where..Thanks again Bob

 

[fugi guy]

Re: Poor Idling 1996 70hp Evinrude...

I found the IDLE screws, on the side of the carbs WAY out of wack.. top was 1.5 turns the center was 2.0 amd the pto was 2.5 ..so i ajusted them all to 1.5 and it seemed to idle better, lower , and not having that shake any more ...I will put it in the water thurs night and try, idling now around 1000 rpm..thanks all..Bob