90 hp runs at WOT

[samo_ott]

Gents, I have a late 80's Johnson J90TLCCA V4 90hp VRO. VRO is disconnected best I can tell. Running 50:1 Got it last year. Worked great for the kids tubing. Did 43 mpg WOT. Just launched it again yesterday for the first time this year. Worked fine for a couple of hours of tubing. Then at the very end when I was coming into the dock the throttle was running higher than idle and I could not shift it into neutral to dock so I just shut it down and coasted in. Today when I started it, it goes right up to WOT (or close to it, can't really tell) as soon as I start it! The throttle is mechanically still all the way down at idle. Checked the carb linkages and they are free and at idle position and move properly. I'm don't know the V4's well as most of my engines are 50's and 60's 2 cylinders. But I would think it's getting fuel injected into it somehow as the throttle plates are closed as it's at WOT. Any ideas?

 

[racerone]

Did the linkage fall off the timer base under the flywheel ??-----Is the timer base moving at all ??

 

[samo_ott]

The timer base appears to be moving fine. That's the linkage that goes from the top of the throttle cam to under the flywheel, right? It's pivoting fine.

 

[samo_ott]

I should add that I lightly hit something under water just before this started. Was just idling in to the dock at the time. We have old logs in our River. No rocks, so it was likely a dead head underwater.

 

[samo_ott]

But even if the timer base was disconnected it should not go to WOT could it? It still needs fuel from somewhere I would think.

 

[emdsapmgr]

After you hit something, you said the idle was higher than normal-that you could not shift it into neutral. That statement means something is broken. Maybe there is something wrong in the control box. Where the throttle/shift cables work together. If it went into neutral, and the throttle was still at high idle, (from being in gear)-it could race at higher rpm's when finally returned to neutral.

 

[samo_ott]

Both cables work fine through the entire range. And it was a light hit at slightly over idle. Throttle linkages work fine and are in their standard position yet it runs flat out. If the cable was responsible then it would be holding the carbs wide open but they are in normal start/idle position.Somehow it's getting extra fuel through the cold start injector or something.

 

[ondarvr]

It needs more than fuel for the RPM's to rise to wide open, or max RPM's, in neutral it can appear to be wide open though, since there is no load on the motor it will rev freely.

Either the timing linkage broke, or the throttle cable isn't working correctly. Both should move freely and fully when you move the lever at the helm. Look down the carb throat and see if the throttle plate moves, and closes completely. Then check to see if the timing linkage moves in its full range of motion and returns to the stop at idle.

Excess fuel flowing into the motor will make it run rough, or stop it from running if the the throttle plate(s) don't open.

 

[emdsapmgr]

Good thought. Check to see that the timer base link arm is still connected to the spark advance lever. (or the throttle lever-depending on the year)

 

[racerone]

Flywheel key ???

 

[samo_ott]

I did not actually take off the cover off the carbs but the two linkages do not move on the sides where the cable lever attaches. So I'm assuming they have not both become detached internally. Which is the timing linkage? The one to the timer base? It is attached and rotating properly as the throttle moves up and down. I have a video but it's too big to post Even the pics are too big to post.

 

[samo_ott]

Would a sheared off flywheel key not make it run rough out of time? It runs smooth and near WOT only. As you as you start it it goes full out. Will check the tach next time to see what it actually reads.

 

[racerone]

A sheared flywheel key could advance the timing and it would run faster and smooth !!!

 

[metriccrescentwrench]

Would a sheared off flywheel key not make it run rough out of time? .....

The timing would be off but it could very well seem to run smooth like that.

 

[samo_ott]

Crap. But that could happen by hitting something so it does tend to make sense. So pull the flywheel and see? I'm only used to older 2 cylinder engine flywheels. Do any surprises await me? Standard puller? And it will re align with the key when I replace it so no messed up timing or anything?

 

[samo_ott]

I should also add that when I turn the red priming lever 180 degrees parallel to the body but in the opposite direction it does slow down and stall out. Does that help at all?

 

[racerone]

That would be adding lots more fuel.---And yes the motor will stall when you do that !!

 

[ForPetesSakeII]

Check the linkage to the butterflies(the thumb screw one) wondering if maybe the plastic pin broke or somehow the butterflys are stuck open??

 

[samo_ott]

Ok, finally got the flywheel off tonight. The key is fine. No issues there. And I took the cover off the carbs and the butterfly valves are maybe 5% open. Looks like a standard idle position. Any other ideas? Still revving like crazy I'm going to repost now with a better title. thx.

 

[1983 ercoa 21']

The throttle blades should be closed at idle.