Bottom carb on 1998 88hp Johnson misting fuel out front

SSPrint

Cadet
Joined
Jul 21, 2013
Messages
11
I have a 1989 88 HP Johnson. After not being in the lake for a year, but having been run every month or so in the drive with water circulation I took it to the lake. Took a couple minutes to get to running right and ran up and down the lake for about 15 minutes. Went to eat lunch and came back and it would run, but no speed... maybe 10-15 MPH. On inspection I noticed that while it's running, the bottom carb mists gas out the front. I removed the carb and disassembled it. Didn't have any new parts to put in it at that time so just cleaned it and made sure of no obstructions. Put it back on and same thing happens. It will run but mists fuel and skips a beat every 5-10 seconds. I changed spark plugs and that?s all. New fresh gas.

I am thinking of swapping the coils to see if it would transfer the problem to the upper carb and thus maybe diagnose a bad coil. Would this work.
Thanks for any help

Mike
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: Bottom carb on 1998 88hp Johnson misting fuel out front

Do a compression test on it. Then check your spark which should jump a 7/16 " open air gap on a spark tester.
 

SSPrint

Cadet
Joined
Jul 21, 2013
Messages
11
Re: Bottom carb on 1998 88hp Johnson misting fuel out front

Checked compression and lowest was 120 highest was 130.

Top plug on port side did not appear to have been firing. I'll check existing posts on how to ck coil.

Thanks
Mike
 

jakedaawg

Rear Admiral
Joined
Jun 26, 2012
Messages
4,275
Re: Bottom carb on 1998 88hp Johnson misting fuel out front

Your reed valves are probably bad, cracked or broken. The misting is from the air being forced back out the carb as the piston pressurizes the crank case. When the reed valves are working properly the block the air from going back out the carb forcing the fuel air mixture into the cylinder. Remove both carbs, remove manifold. The reed valves are the little things that look like fingers. They are little flappers so to speak. treat them very carefully.
 

DargelJohn

Petty Officer 1st Class
Joined
Feb 14, 2010
Messages
337
Re: Bottom carb on 1998 88hp Johnson misting fuel out front

I would also say it's reed valves.
 

SSPrint

Cadet
Joined
Jul 21, 2013
Messages
11
Re: Bottom carb on 1998 88hp Johnson misting fuel out front

Your reed valves are probably bad, cracked or broken. The misting is from the air being forced back out the carb as the piston pressurizes the crank case. When the reed valves are working properly the block the air from going back out the carb forcing the fuel air mixture into the cylinder. Remove both carbs, remove manifold. The reed valves are the little things that look like fingers. They are little flappers so to speak. treat them very carefully.

Are they usually repairable (cleaning, removing debris) or should I plan on replacing. Some folks on here have good things about the aftermarket reeds made by Boysden or something like that ...can't remember the exact spelling but I can find it again.

Thanks much for the advise.

Mike
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,135
Re: Bottom carb on 1998 88hp Johnson misting fuel out front

If there is just gunk holding it open then you can fix it but if one is cracked/bent then you will need to order the replacement reeds for the affected carb and the gaskets.
Id have no worries using a second hand reed unit
 
Top