Idle timing screw? Johnson 140

[archcycle]

1990 Johnson 140 V4

The OMC manual says to adjust the idle timing with the idle timing screw. I don't see D on my motor.

 

[clanton]

Re: Idle timing screw? Johnson 140

Did you look behind the wires behind the starter. Service and parts manual show it. The bracket is held on by the same screws that hold the upper crank bearing housing. There is service bulletin that covers item A and B photo7 page 1-45.

 

[rtek816]

Re: Idle timing screw? Johnson 140

Look on the other side of the flywheel.......

 

[archcycle]

Re: Idle timing screw? Johnson 140

Behind the starter is what I thought the picture looked like, but here are images all around the starter:


The image in my previous post is from page 1-45 of the manual

Am I just being blind here? This should be on the port side attached to the timer base, right?

 

[archcycle]

Re: Idle timing screw? Johnson 140

Look on the other side of the flywheel.......

Here's the other side of the flywheel:



If I am interpreting the service manual picture in post 1 there should a bracket holding a bolt with a spring pushing a lever attached to the timer base and it should be on the port side, opposite the spark advance screw business on the starboard side. Is that wrong?

 

[clanton]

Re: Idle timing screw? Johnson 140

Post your engine model number, I will check the service bulletins. I have ths OEM manual in my hand now, photos of V4 powerhead shows this adjuster. BPR parts site also show this adjuster, on the page with crank and pistons.

 

[archcycle]

Re: Idle timing screw? Johnson 140

It doesn't have a model number on it; it's one of "those" motors. The core plug says G2491987 which BRP identified over the phone as J140TLES.

 

[daselbee]

Re: Idle timing screw? Johnson 140

You see the black cigar tube looking thing on the stbd side? The thumbwheel on the end? That's it.

You will see that as you turn that screw on the end, that the timer base moves.

 

[archcycle]

Re: Idle timing screw? Johnson 140

 

[daselbee]

Re: Idle timing screw? Johnson 140

What's your point with the pic above.?

The pics you have posted apparently do not apply to your motor. It must be frankensteined.

The screw under the flywheel, inboard of the black tube with a spring in it, is the WOT stop screw for the timing advance.
The black tube is the timing adjustment for the idle timing.

The stuff on the other side of the flywheel doesn't exist.

As you travel down the throttle arm from the top, you will come to a screw, head facing forward, end of screw capped with a rubber tip....that is the idle stop screw.

Just below that, facing the opposite way, looks like the WOT stop screw.

I am just going by the pics you posted.

EDIT: the black tube idle adjustment looks broken, too.

 

[archcycle]

Re: Idle timing screw? Johnson 140

The point of that pic was to show that those parts in the service manual had corresponding part numbers on the parts charts and that their names did not match up with what the manual called them and some are apparently outright missing from my motor. And yes, I do have a frankensteined motor, thanks for noticing

That said, good advice as usual Daselbee

Verified that cranking that thing down all the way did increase the idle timing so it's ready to set in actual conditions next time I get on the water.

 

[daselbee]

Re: Idle timing screw? Johnson 140

I will go look to see if I have a good idle spark adj tube.....it is iffy, those things break, and if I am not mistaken, they are NLA.
Christmas may come early, just let me look.

And yes, as you turn that rod, you will see the timer base move under the flywheel.

Disconnect throttle cable.

Sync carb butterflies so they move in perfect unison, and all four are all the way closed when in idle position.
This has to be perfect or it will not idle right.
Set idle stop screw next, where the rubber hits the block exactly when the throttle butterflies are closed all the way.
Set WOT stop screw so that when at WOT, the butterflies are horizontal, and not over-travelling past horizontal.

EDIT: Not horizontal...but open fully and in line with the throat of the carb. I used the wrong word "horizontal".

Then, set the cam roller so that it lines up with the mark on the throttle cam. Start it, set idle timing to obtain 700-750 in the water.
Lastly, set WOT timing using Joe Reeves method, or on the water with a timing light at 5000 rpm. (That's the way I do it.)

Adjust cables and connect so there is no tension at all in order to slide it over the cable connection pin. Should slide right on without having to push it or pull it.

That will get you real close to a correct link and sync.

 

[archcycle]

Re: Idle timing screw? Johnson 140

Update: I got it all synced up on Saturday and set the timing. It was off by 3* at idle and 2* WOT. We were able to set WOT running on the water at 5k.

it. ran. great. Not only did the cough and sputter at idle it had developed in the last year disappear but the midrange throttle response was like a night and day transformation.

The butterflies were still well synced from when I did this about a year ago but I loosened them up and started clean anyway.

The throttle cable was the serious offender for the idle. I always thought it was fine because it slipped on and off easily but I gave it some serious inspection this time around. After opening up and going back to N on the controls it left some play and would only sometimes actually push and hold that last millimeter or so to fully close the butterflies. So when many times I couldn't figure out why it would randomly idle well after backing the throttle off or else cough and sputter, it really was random. Sometimes the butterflies closed fully and sometimes they didn't. Trial and error of 1/4 turns got it to a spot where it could go full WOT, return to N with the butterflies fully closed, and still slip on and off.

The D shaped metal pin that pivots to move the plastic throttle arm seems to have worn some play into the fitted D shaped plastic throttle arm which is resulting in a little bit of play in the linkage that is keeping the port side butterflies from coming perfectly to 90* open with the starboard, but it was a sacrifice that had to be made to get them to completely close together. With the play in there it was one or the other no matter how much I messed with the screw that tightens them into place since the round side gets the screw and the flat side doesn't. It is really close at WOT though so it's probably no problem.

 

[daselbee]

Re: Idle timing screw? Johnson 140

Arch, all I have is this type here. I think it will work for you, just don't know about the access to the screw with the air silencer on.

PM me if you are interested.

 

[archcycle]

Re: Idle timing screw? Johnson 140

I really appreciate the offer but now that it's all set and and timed with the current hardware, it's probably best if I just don't touch it. Here's how it all turned out: