1977 35 h.p. Evinrude throttle pushes back!

Hi all, what would cause my 35703C to push, as if it had the muscles to do so, its own throttle down to nothing, while sputtering out? This only happens when I try to bring it back from a high throttle start. It will run all day in neutral at any speed above 1/4 throttle or so. It will also run in forward gear this way, though I'm not sure for how long, I didn't want to leave the bay with a questionable motor. Below that, it drops its' own rpms to an eventual zero. It's pushing against my hand on the throttle, at the control box or back at the motor with the cables disconnected. New teleflex's by the way.

I bought this motor from a mechanic, and it worked fine, for about 2 running hours.
Then it ran rough, inconsistently, and would dog down at high speed.
Then I let it sit for a long time. Too long.
Then I took it to a mechanic, I was afraid I would mess up the adjustments and the small unknown intricacies of the carb, although I "knew" the carb just needed a rebuild and I would be off. He also replaced a bad ignition coil. And the fuel pump.
Then, I took it out and it was perfect, except: under power, it would get up on plane, then 2 seconds later going up and down in throttle in its full range, think of it as the motor as screaming: Wow! Wow! Wow! over and over.
Then I replaced the other ignition coil.
Then I replaced the vacuum hoses and major electrical lines.
After no progress, we took it to another mechanic. They replaced the two coils under the flywheel, the sensor coil and...bah, can't think of it now...the bigger one. They also replaced the upper crank seal, as it was bad, and thats what burned out the coils, yada yada.
Now, this is where I'm at. All I can think of is the stator, now. Or the power pack. But, that doesn't make sense. Could it be an internal, more major problem? Compression is good, spark plugs are new and gap is good. Idle needle in front of carb is well adjusted. Fuel externals(bulb, tank itself, etc.) are also good. Thanks for the help, guys.

Re: 1977 35 h.p. Evinrude throttle pushes back!

All that seems to be left is the fuel pump. Have you checked the spark youself? You will need a basic spark tester from any auto parts store ($10), and make sure it can jump a 1/2" or 7/16" gap with a strong blue spark. If spark is good (and from all you have replaced it sounds like you should have good spark), move on to fuel issue. Maybe the pump is just dying.
How old is the gas in the tank?

Re: 1977 35 h.p. Evinrude throttle pushes back!

I don't understand. It sounds like you are describing two didderent problems, one a performance problem and two, a matter of it physically moving the throttle control.

Physically moving the throttle control is something dragging on the flywheel magnets (coils or loose parts). Could also be loose main bearings allowing the crankshaft & flywheel to move back and forth and rub the coils. Sounds like you need a different mechanic.

Re: 1977 35 h.p. Evinrude throttle pushes back!

F_R said:

Physically moving the throttle control is something dragging on the flywheel magnets (coils or loose parts). Could also be loose main bearings allowing the crankshaft & flywheel to move back and forth and rub the coils. Sounds like you need a different mechanic.

Click to expand...

Agreed.

Re: 1977 35 h.p. Evinrude throttle pushes back!

It sounds like a lot of mechanics have been involved already. He bought it from one and then had 2 other different ones look at it. That's a lotta mechanics!

Re: 1977 35 h.p. Evinrude throttle pushes back!

That's true. Makes ya wonder doesn't it? Aren't these guys checking their work? Or is that just what happens "up north" when the water is frozen? I never would have survived putting out repairs that haven't been tested.

However, the owner has been able to test run it so the water isn't frozen for him. Sounds like some H-raisin' might be in order.

Re: 1977 35 h.p. Evinrude throttle pushes back!

Hmmm... How do you know it was an up north mechanic? It sounds to me like a southerner!

Re: 1977 35 h.p. Evinrude throttle pushes back!

Thank you guys for your input, truly appreciated.
I agree that at least one of the three mechanics is either untrustworthy or incompetent.
Gas is new, with a little Seafoam in it, 50:1 walmart 2-stroke oil.
Fuel pump has been newly rebuilt personally, so that I can guarantee. I did the primer bulb test and everything's good there. Fuel lines are also OK.

The pushing back part...it appears to be a result of the sensor plate, or something connected to it, oscillating the throttle due to it's own oscillation during lower rpm's...that's when it runs rough, you see the sensor plate and some other stuff really shaking, and the "pushing back" may just be due to the inherent tension in the cable plus the shaking....perhaps I should just try a forth mechanic, eh?

I've read the Clymer manual front to back, have decent mechanical aptitude, but I still feel very much in the dark about working on this engine.

I am currently in Gainesville, FL. Go Gators!

Re: 1977 35 h.p. Evinrude throttle pushes back!

It sounds to me that the flywheel magnets are touching thedriver coil, sensor coil, or both. Pulling the flywheel and coil adjustment is in order.

Re: 1977 35 h.p. Evinrude throttle pushes back!

Thanks, guys...since I'm going back down with the boat in 2 days, might as well give this mechanic one more try, see if he'll correct his work for free...he is trusted to fix our family's cars, so...but yeah the last thing was replacing the 2 coils under the flywheel, so that makes sense. So, I still can't even tell from the parts catalog online...where does the stator fit in all this? Not around the sensor plate, right? Under it? And, should the sensor plate ever move at all? Once again, thanks for your time.