1996 88hp johnson idle problems

About 4 months ago the 88 had a slow idle and I adjusted the idle speed screw (closest to the flywheel) to pick it up a bit. And once again about 2 months ago. Now the 88 starts fine and will run great until I shut it down and try to restart after about 30 min. or longer of fishing, then the idle is very slow or non-exsistant and seems to have a miss, rattling the entire boat, have to quickly advance the throttle (in neutral) to keep it running, and once underway it's fine. Then when coming down off plane, the idle is once again very slow and will even die unless I advance the throttle. Installed fresh plugs, de-carbed the engine, fresh gas and filter, replaced plastic cable ties with ss clamps. checked spark-ok, timing is way off, carb cover says 28 BTDC, but I got 12 BTDC, I think the carbs need rebuilding (by the way, it runs fine on the hose)<br />Thanks to this forum I've been able to find some of the possible causes, man this is great, wish I had found this site sooner!... Dave

Re: 1996 88hp johnson idle problems

Hey Dave! Welcome to iboats.<br /><br />Lets' talk timing first. At what rpm did you check it at? The timing on the carb cover is high end timing. This should be set at WOT with a min of 5000rpm.<br /><br />I would give the engine a good going over. Get compression readings, check the spark and make sure the basics are in good order. Sounds like you've taken steps in that direction already. It wouldn't hurt to document what you've done and keep it handy for future reference.<br /><br />If you havn't touched the carbs since owning the rig, now would be a good time to do so. The idle problem could be some junk floating around in the bowls and plugging up the jets. This is not good since it could mean a lean mix going into the cylinder and this in turn will cause a wipe or scuff in the cylinder.<br /><br />And if you don't own one, get a manual. It will guide you during the work. Don't hesitate to post if you have any questions....thanks.

Re: 1996 88hp johnson idle problems

I checked the timing at idle, I picked up a tach last night so I can get the rpm reading, but I'd guess the rpm was about 8 to 900 when I checked the timing. I thought the the miss was lack of fuel flowing through one of the carbs or no spark in a cylinder. I'm planning to rebuild the carbs...any advise before I start?<br />I've got a book, I just wanted to find out if I an going about this in the right way. Should I reset the timing after the the carb job or wait and see how it runs afterwards? Thanks for your reply - Dave

Re: 1996 88hp johnson idle problems

Check if your stator plate moves frely, is sounds like it doesnt get down to iddle timing. 12 is to far advanced to iddle as far as I remember.

Re: 1996 88hp johnson idle problems

If that engine performs fine at WOT , your full advanced timing is probably ok.They don't get out of time very often.However the idle timing is held in place by a timer plate return spring that is clearly visible just below the flywheel.If this spring becomes dislodged from the tab that contains it ,it will hold the idle timing up and not let it drop back fully.If this spring is not out of place,Your problem sounds to be either idle porting carb restrictions or a carb synchronization issue.

Re: 1996 88hp johnson idle problems

Thanks guys, this is great info...Dave

Re: 1996 88hp johnson idle problems

I have completed the carb rebuild and was getting ready to reinstall, then I was looking for the timer plate return spring refrenced above, and cannot find a spring under the flywheel anywhere and the manual doesn't show it either...Dave