Johnson V4 throttle and timing linkage sticking - Help

[Louisdm]

Hello all!,

I have a 1978 Johnson 115hp V4 and noticed when I move the throttle linkage forward the timing linkage is not moving forward together with the throttle. The timing linkage seems to be sticking and moving much slower. It's supposed to move together with the throttle at the same time correct?

Also both are not moving back to the idle stop automatically which is what it's supposed to do right because of the spring? It's somewhat difficult to push both linkages back to the idle stop. I uploaded a short video so you can easily see the problem - https://youtu.be/ulkvyDU3SxU

Would this issue cause the engine to die once I put it in gear and apply the throttle via the controls? That's the problem I'm dealing with and hoping this is it.

Thanks for the help!

Louis

 

[interalian]

Looks like the timer base has old dry grease. You can spray some WD-40 around where it pivots then work it back and forth like you're doing in the video. The WD-40's solvents will re-activate the grease. Don't go nuts with the WD-40 - a little will go a long way.

If you want to do it the hard way, remove the flywheel and take it all apart.

 

[Louisdm]

I sprayed some WD-40 where it pivots under the flywheel and it definitely helped, but I'm still unsure it's working properly.

Now the timing linkage quickly moves forward but only once the throttle is around 3/4 to almost full which is when there's max pressure from the throttle spring pulling it forward.

Is the timing linkage supposed to move forward perfectly in sync with the throttle?

 

[interalian]

The timing arm is spring loaded and linked directly to the throttle arm - they move 1:1. Idle speed is set by timing alone, with slight fuel bleed through closed carb plates.

When opening the throttle, the timing arm moves in sync with the throttle arm (1:1) until the timer base touches the rubber tipped stop up at the top, then the throttle cam opens the carb plates which are partially open just as the timer base hits the stopper.

Maybe make another vid clip to show what it's doing now?

 

[Louisdm]

Thanks, made another video clip to show what it's doing now- https://youtu.be/pBoMTP7Rj2g

The linkage doesn't move 1:1 like you mentioned, it starts moving forward a bit later as you'll see in the video. Looks like around half throttle when the timer base hits the rubber stop.

Do you think this issue could be the reason the engine dies when put in gear and throttle is applied? I still have a lot of other things to check such as spark, fuel pump and carbs, but it starts and idles great now.

 

[F_R]

It is NOT moving correctly. When you start pushing on the control arm, most of the movement should be to the timer base (spark advance). There should be only slight movement of the carburetors during this phase. It is only when the timer is at full advance against the stop, that the carburetors then quickly open during the last bit of movement of the control. Yes, what is happening in your videos absolutely will cause stalling as you attempt to increase speed. You need to take that timer base mounting apart and clean/re-lube it.

BTW, the problem you are experiencing is quite common and well known .

 

[interalian]

Yeah, still sticking.

"Mechanic in a Can" could still work but you would be best off removing the flywheel (need an harmonic balancer puller with long 5/16" NF (fine thread - most come with coarse) bolts) to get the flywheel off. Loosen the flywheel nut a few turns but leave it on whilst using the puller so when it pops it doesn't go flying. You'll need a flywheel holding tool for loosening and tightening the nut.

Once the flywheel is off you'll see what you need to do. Make sure once you have the timer base clean and lubed that the wires don't bind when it rotates. Lithium grease.

When re-installing the flywheel, make sure the key is in place (parallel to the crank, not flat to the taper) and the tapers are clean and dry (use brake cleaner or similar no-residue cleaner), and torque the nut properly. Somebody correct me if I'm wrong, but 105 lb/ft torque on that nut. If you don't torque properly you'll shear the key when you run the motor.

Oh, and don't be tempted to diddle with the timing stop. No need to loosen or adjust it.

 

[Louisdm]

Thanks appreciate the help! I ordered a flywheel puller today and also a new throttle spring, maybe it's worn out? Hopefully I can tackle this project in the next couple weeks.

 

[F_R]

I've never seen a bad spring. But it never hurts to think, I guess.

 

[interalian]

If you take the split pin out of the timer arm up at the top, disconnect the link and then move the timer base manually, does it feel stiff? If so you have dried grease. I doubt there's anything wrong with the spring on the throttle arm.

 

[Baylinerchuck]

Also something I found on my 1978 85hp Johnson was the plastic sheath covering the timer base cable assy was extremely hard. I guess years of exposure to fuel made it brittle. That alone made my timer base act the way you describe. I carefully cut off the hard plastic. I installed new spiral wrap secured with tie wraps at either end. Once I did that the harness was again flexible, and the timer base advanced and retarded properly.

 

[Super18]

Thanks Baylinerchuck! This is the only place this problem was referenced & if I hadn't read it, I'd still be chasing the problem. You saved me some serious headaches!