Initial screw adjustments 2000 135hp

[red boat]

The throttle body of my 2000 135 johnson has 4 adjustment needles. when cleaning the carbs each one of these screws was out from 4 to 5 1/2 turns. what should be the initial turns out from being seated to start fine tuning them. what do I "look"? for as far as running quality adjusting these screws. The motor model #J135PLSIF. sorry about long post just trying to get all the info.

 

[red boat]

Re: Initial screw adjustments 2000 135hp

No one has any experience with this adjustment??

 

[R.Johnson]

Re: Initial screw adjustments 2000 135hp

It is 3 1/2 turns out from the bottom. When you get the engine running, adjust 1/8 turn, in, or out until engine runs the smoothest. Best done in the water.

 

[red boat]

Re: Initial screw adjustments 2000 135hp

Does turning them in lean or richen the mixture, I would assume it leans it? The engine does run, I just put a I-boats reman powerhead on and am having some problems with a terrible idle and lack of WOT. I have rebuilt the carbs, cleaned throttle bodies and done a sync and link. I just hot thru the 10hr breakin and now it will only turn 4600 rpms. It would turn 5700 on hours 8, 9 and 10 of breakin then all of a sudden rpms went down. I am at a loss as to what might be causing this. I am going to remove the carbs and reclean them and redo the sync again. The timing base is going to the stop and timing is set at 18deg at WOT. I dont know if this is a fuel or spark issue. I have pulled all 4 plugs and checked and it has a strong spark on all 4 cylinders. Any ideas as to where/what I might try looking at first. Will it cut rpms down due to a fuel restriction?

 

[R.Johnson]

Re: Initial screw adjustments 2000 135hp

Just to make sure, do a compression test.

 

[red boat]

Re: Initial screw adjustments 2000 135hp

I will do a compression test saturday and post results.

 

[red boat]

Re: Initial screw adjustments 2000 135hp-Problem Solved

Re: Initial screw adjustments 2000 135hp-Problem Solved

Compression tested and 1,2,3,4 all showed 135psi compression. Removed and re-cleaned all 4 carbs and throttle plates and readjusted the idle screws per R.Johnsons recommendation, removed and cleaned vro pump, flushed all hoses. loosened all electrical connections and cleaned all terminations with sandpaper. Unplugged all electrical plugs and cleaned by spraying with GumOut carb cleaner. Launched the boat and still had a very irratic idle. By putting a timing light on each plug wire I discovered 1 cyliner was not firing, by swapping that coil with one of the others the problem followed the coil, so that was the problem? Not with my luck :'(Replaced the coil and it ran better but was still idleing rough. :devilutting the timing light on each coil wire again. Cyls. 1 & 3 showed perfect fire but every 10-15 seconds at idle the timing would advance for just a quick second from 4 to 12 degrees. Cyls 2 & 4 were firing but very very erratically. Purchased and replaced the power pack and the problem was solved. Put another hour on the new powerhead and the rough idle problem has been solved!!8)

 

[DJ]

Re: Initial screw adjustments 2000 135hp

Great diagnosis. Good job. The timing light is a useful tool for finding those gremlins.