9.9 Johnson 4 Stroke Won't Rev

[Scondo]

9.9 Johnson 4 Stroke Won't Rev

Hi Fellow boaters<br />I have a 2002 9.9 4 stroke which will idle ok but when i try to rev it it revs up a bit but sounds like it is labouring as well as vibrating.<br />have checked plug gap and set it to 0.8 mm.Removed carb and given it a good clean it needed it,blew it out with compessor.Engine has had very little use 15 hrs ,been sat for a long time.Any help welcome.

 

[Walker]

Re: 9.9 Johnson 4 Stroke Won't Rev

Re: 9.9 Johnson 4 Stroke Won't Rev

How about your fuel Mers?? Is it fresh?

 

[Scondo]

Re: 9.9 Johnson 4 Stroke Won't Rev

Re: 9.9 Johnson 4 Stroke Won't Rev

Hi Walker <br />Yes i have thrown out the 2 month old fuel and put freash stuff today.

 

[Solittle]

Re: 9.9 Johnson 4 Stroke Won't Rev

Re: 9.9 Johnson 4 Stroke Won't Rev

Check for spark on both cylinders.

 

[Scondo]

Re: 9.9 Johnson 4 Stroke Won't Rev

Re: 9.9 Johnson 4 Stroke Won't Rev

Have run it with freash supply of fuel,put those cap things on HT leads while it is running and looks like spark at both plugs.Just need to do a compression test.

 

[scott_gillroy]

Re: 9.9 Johnson 4 Stroke Won't Rev

Re: 9.9 Johnson 4 Stroke Won't Rev

also try any get some evinrude/johnson engine tuner at your local dealer and spray in your carb and spark plug holes let it set for about a hour or so and start it up and wathch all the black stuff come out of the prop

 

[Scondo]

Re: 9.9 Johnson 4 Stroke Won't Rev

Re: 9.9 Johnson 4 Stroke Won't Rev

Have spayed some of the mercury power tune in the carbs and in the cylinders and left it for 3 hrs and ran it uo again and no luck so have srayed a pile more in and left it for over night and will see tomorrow.I have also done a compession check it is 145 on both cylinders.Also did a leakage test on the cylinders and that seems ok .BUT when i run it it has a lot of crankcase presure,if i take of the oil filler cap it blows out of there,does this not mean that compession is leaking past the rings ??.

 

[Scondo]

Re: 9.9 Johnson 4 Stroke Won't Rev

Re: 9.9 Johnson 4 Stroke Won't Rev

Hi All<br />have run it up after the power tune and a new set of plugs and it it running much better but at mid range on the throttle it seems to bog ,and just does not seem to be reving with a full throttle power

 

[Scondo]

Re: 9.9 Johnson 4 Stroke Won't Rev

Re: 9.9 Johnson 4 Stroke Won't Rev

Hi all .<br />Have it sorted now ran it under load on the boat and it seems to be fine .than x for all your help.