1988 Johnson 60 idle issues....HELP!

Buickmike

Seaman Apprentice
Joined
Mar 7, 2016
Messages
37
Hello all.....
Engine is a 1988 # J60TLCCR .
New to me. When i got the boat/motor it ran great on the muffs, shifted into fwd and rev and revved fine in gear and neutral.
First time in the lake it started and idled fine. Shifted into gear and throttle to first detent= all fine. As soon as i tried to push it past that point it would bog down and stall. I tried a half dozen more times with squeezing the bulb with no change.
Fast forward to now......i had the carbs professionally rebuilt, all fuel lines changed, 2 different fuel tanks with fresh mixed gas (50-1) compression is 120 on all 3.
coils have been tested and are good. charging is good. new champion plugs gapped to .30. all electrical connections checked and or repaired with new connectors and heat shrink. link/sync done.
The motor runs fantastic at high speeds now, it sounds way nicer on the muffs than it did before. starts right up and the bulb stays hard.
The problem is that now i can't get it to idle lower than about 1200+ rpm on the muffs. My mechanic is doing all of this work and once she tries to adjust the timing advance back the motor starts to stumble and miss....at around 1200 she smooths right out and runs like a dream.......
So...after perusing this awesome board, i have a couple of questions.
1- what should the idle on muffs be for this motor?
2- could this possibly be a power pack issue?
Thanks in advance for any help!
Mike.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
This engine is not a good idler. I've had two of them. You should be able to get the engine to idle well enough at or just below 1000 rpm's. Your carbs are not the later carbs that have the idle mixture screws, so your idle is pretty much set by the size of the idle jets. Maybe your idle jets are clogged with debris? You can't set the idle on the muffs with this engine. You set the idle when the boat is floating in the lake and is in forward gear. You can't set it out of the water. Also, the idle is controlled by the idle timing-not by carb mixtures. See your factory manual. If your engine runs great at WOT, you don't have a power pack issue.
 

flyingscott

Fleet Admiral
Joined
Apr 8, 2014
Messages
7,985
AGREE with everything above. 1200 rpm on muffs should be ok it should drop to about 1000 rpm in water. Your idle needs to be set running in gear and good and warm you do not care what it is on muffs. They are not great idlers they are a rougher idle but they will idle.
 

Buickmike

Seaman Apprentice
Joined
Mar 7, 2016
Messages
37
Thanks emdsapmgr!....
I will get her to set it in a barrel and try in the lake this weekend...
 

flyingscott

Fleet Admiral
Joined
Apr 8, 2014
Messages
7,985
Thanks emdsapmgr!....
I will get her to set it in a barrel and try in the lake this weekend...


Your idle needs to be set in the lake after it has gotten warm a barrel is not going to cut it. You need to be able to throttle it up after the adjustments.
 

Buickmike

Seaman Apprentice
Joined
Mar 7, 2016
Messages
37
Thanks flyingscott!...im just going to set it as low as it will go in a barrel and then fine tune it as per you guys instruction. Its a relief to know that this seems to be typical of these engines, i was getting worried it was going to be heating up the ole visa pretty quick...lol
 
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