1985 140 Looper dies at Idle

[gokart83]

rebuilt carbs, this is a new motor to me, new fuel lines from tank to carbs, low idle and shuts off when its warmed up and in gear. This is making it very hard to load the boat on the trailer. Dads neighbor said to stick toothpicks in the small idle air bleeds and break them off and set the timing at 24 deg instead of 22 deg due to the fuels we run nowadays. Does that sound right? Also, what size jets (low/high) did these motors come with and what should they be if different? there are 2 different sizes listed as OEM parts. Thanks for yalls Help!

 

[clanton]

Re: 1985 140 Looper dies at Idle

The standard jet sizes should be listed in the OEM parts manual, and OEM service manual.
OEM did not recommend full timing advance be changed. There are at least 3 service bulletins for this engine,
1 for idle/idle timimg linkage, 1 for thermostat seats, 1 for thermostats. All three affect idle.

 

[clanton]

Re: 1985 140 Looper dies at Idle

The difference in the jets in the OEM manual are 1 size for the 120, 1 size for 140. The gasket on the side of the carb should be checked, vacuum will sometime suck the gasket into the passage, blocking it.

 

[lexer440]

Re: 1985 140 Looper dies at Idle

I had an almost similar problem with my 140, checked everything and couldnt find issue. I discounted temp as an issue because i disabled it during sync and link and motor did get hot to touch when running. Finally got a temp gun on heads and although they got what i called hot they were not hot enough to disable QS when running. new thermostats and it was fine, running temp now is around 120 deg. A note on the thermostats, they were old ones and the new ones i received were a modified design, apparently a mod kit came out for them about 20 yrs ago, thats how old mine were.

PS. my 140 is an 88, i do not think you have quickstart, really just making reference to poor temps as a possible cause.

 

[CharlieB]

Re: 1985 140 Looper dies at Idle

Idle problems after carb rebuilds are often caused by failure to use all new gaskets and/or not 'completely' cleaning all fuel and air circuits.

Recheck your work.

The toothpick tip is WRONG, a single tooth pick may be helpful to temporarily restrict airflow while diagnosing a problem to see if it changes idle quality, but should NEVER be broken off and left in place.