The Boating Forum - adjusting the idle 90hp johnson, pics incl

Guys,
i am trying to adjust my idle rpm's without a timing light or typical manual.
I know that we set idle by getting the timing just after tdc. about 4deg atdc.
When i get the idle around 800rpm's i have this bog just above idle, when the butterflies of the carb start moving. It is like a misfire/bog, but getting more fuel by priming it a few times won't cure it good enough. When i set idle rpms around 1000 that bog is diminished for a great deal.
Can my tachometer be out of sync and telling me wrong rpms?
Do i have to set idle at 800 rpms and adjust the carb linkage? Do get rid of that misfire at 1/8 throttle?
Is it time to clean some passages in the carb?
This motor is new to me, although from 1991.
When starting i get this big puff sometimes, has it to do with not enough fuel. Or are some of the reeds going south?
http://i194.photobucket.com/albums/z120/geoann/DSC_2195.jpg

You aren't gonna guess your way to a base setup.
Get the factory service manual, half price here.
http://stores.ebay.com/SEARAYMAN13/EVINRUDE-JOHNSON-1991-present-/_i.html?_fsub=10&_sid=27070634&_trksid=p4634.c0.m322

Initial startup of OMC outboards produce alot of smoke. It's normal. The timing is never adjusted unless the engine is taken apart. The misfire/bog, above idle is indication that your link and sync is off. If you're idling at 800 rpms on a hose, then it's too low. Back pressure of the lower unit in the water is critical. As jonesg suggested, get a manual.

I have to correct something.....I have a clymer manual but it is very allround, and not very specific for the spooler 91 90hp.
It does mention the way to adjust the crossflow so i assume it will almost.... be the same for the spooler.
So, yes i do have a manual. And it does give some guideline about adjusting the idle/sync.
I adjust the idle in the water in forward gear.
What wld be the best way to adjust the timing? Disconnect the throttle cable and manually alter the timing till its rpms are best, or lowest, and go from there?
Disconnect the link to the carb aswell. So just moving the timing plate?

so i borrowed a timing lamp. Guess what.... when mine 90hp idles at 900rpms it fires around 4 degrees after !!! tdc :o.
When i adjust the timing to the manuals 4 degrees before tdc it idles at 1200 rpms.
What wld that tell us....;?
Do i have a air leak? Or are the slowspeed jets dirty causing it to act lean?
Compression tested all 4 cilinders and they are within spec. 120/115/112/118.

Tomorrow i will take a good look at the sync, butterflies etc.
Maybe they are a little off sync.
Next on my mind is cleaning the carbs. Have got the gaskets/kit on hand now.

Btw i have the crossflow not the spooler. So the clymer is much more handy now that i know that.:grin:

so i borrowed a timing lamp. Guess what.... when mine 90hp idles at 900rpms it fires around 4 degrees after !!! tdc :o.
When i adjust the timing to the manuals 4 degrees before tdc it idles at 1200 rpms.
What wld that tell us....;?
Do i have a air leak? Or are the slowspeed jets dirty causing it to act lean?
Compression tested all 4 cilinders and they are within spec. 120/115/112/118.

Tomorrow i will take a good look at the sync, butterflies etc.
Maybe they are a little off sync.
Next on my mind is cleaning the carbs. Have got the gaskets/kit on hand now.

Btw i have the crossflow not the spooler. So the clymer is much more handy now that i know that.:grin:

Follow the link in my signature to used factory manuals at .50cents on the dollar, you can't beat success, throw the clymer away, it is known to have incorrect specifications.

Once you have the book, rebuild the carbs, run wire thru the jets to clear them..cleaner isn't enough.

Baseline the engine to spec, link and sync it and see whatchaget.
Usually if the WOT is set properly the idle will be good.
Idle adjustment is used to set idle speed, 700 in the water at idle in fwd gear.
Its all in the book in detail.

before you pull anything to pieces, BUY the manual for your motor (as mentioned) and set it up correctly, I guess by "spooler" you mean "looper"? after correct setup, any carby rebuilds may not be needed (but they may) so be sure before you introduce another fault.