1989 Evinrude 100 XP... Runaway

[tallcanadian]

Has anyone ever experienced this? What an ordeal. However from what I've researched, it isn't an uncommon issue. I haven't tried since to run it. I'm a little worried it may happen again. Dang thing was so hot. I did have it on muffs and was having problems getting it started so I put a bit of gas in each cylinder. Put the plugs back in and it started all right. Revved wide open it seemed. Turning off the key did nothing. I had to in hook the gas and let it run out or blow up, which ever came first.

What I did do after was check my grounds. Everything is okay. Checked the carbs again, butterflies were closed. Apparently even if you pull the plugs wires off it would have still ran like that.

So I guess I will put it in a barrel next time to see if this thing is still living.

 

[boobie]

Have some rags handy the next time you start it and if it happens again stuff them in the intakes for the carb air box.

 

[tallcanadian]

I've already checked that one off my list. Lol.

 

[rothfm]

Geeze, 1st ensure your OFF is working ok by grounding the yellow/black wire on the Pack. Ensure your linkages are conected and ok. Should be no reason to runaway unless linkage or advance are is off....Possibility is the flywheel key also. I had one that was some-what out of control speed-wise due to a bad key.

 

[interalian]

This is why you frequently see comments about not revving too high in neutral. Too much fuel and advanced timing used to start (probably had the idle lever up, no?). Once it hits, there's initially enough fuel to run it off the scale and it sucks more fuel through the carb butterflies (notched if you look), getting ignition from hotspots in the combustion chamber. The only way to stop it is to choke off the air as boobie said, unless it grenades by itself.

 

[Bosunsmate]

Yep ive being in this situation i remember it well, i pulled the gas plug connection off too, it was a bit of a weight up the situation moment, do i risk myself or my motor and i took the wrong choice and risked myself, i had being hiding around the side of the house for about ten seconds waiting for it to blow but it never did.
I fixed what caused it in mine, worn upper and lower crankcase seals causing it to run lean and its being a sweet as motor ever since. It didnt damage it yet it was a very high rpm for at least forty secs so good luck with yours

 

[tallcanadian]

This is why you frequently see comments about not revving too high in neutral. Too much fuel and advanced timing used to start (probably had the idle lever up, no?). Once it hits, there's initially enough fuel to run it off the scale and it sucks more fuel through the carb butterflies (notched if you look), getting ignition from hotspots in the combustion chamber. The only way to stop it is to choke off the air as boobie said, unless it grenades by itself.

I did have the throttle lever up. And putting fuel directly into the cylinders, priming it. I guess that was the recipe for disaster. Everything looks good but I'm going to pull the carbs again and chech them out. And I'm going to put it in the barrel as well.

 

[tallcanadian]

Yep ive being in this situation i remember it well, i pulled the gas plug connection off too, it was a bit of a weight up the situation moment, do i risk myself or my motor and i took the wrong choice and risked myself, i had being hiding around the side of the house for about ten seconds waiting for it to blow but it never did.
I fixed what caused it in mine, worn upper and lower crankcase seals causing it to run lean and its being a sweet as motor ever since. It didnt damage it yet it was a very high rpm for at least forty secs so good luck with yours

I was waiting for something to come through side. I was actually ducking as went from side to side trying to shut this down. Lol. I probably looked like I was doing the chicken dance. How did you figure out your crank seals were bad?

 

[Bosunsmate]

Ha ha sounds like you went for the indirect approach too, mine was screeching so high i was almost certain the whole thing was going to blast apart.

I figured it might be the seals due to elimination. I had bought it off the head mechanic at a shop whose motor it was and he said he had tried everything to fix it, he was certain it had a gremlin (and i almost believed him at this point). But i figured since it did the run away that it was either having a timing issue and or a lean issue. Timing checked out well and i sprayed engine starter around the carb gaskets and the crankcase and revs didnt change so i figured id spend some time on her one day as a last chance saloon and replace the seals. (Its a 60hp) so only two cylinders. I replaced them, Just the top and bottom ones which you can get at from the outside by pressing them out. I put her back together and she went straight away into a nice idle and was ready for work. Amazing what this one handled, it would of being beyond any redline.
I did lap the head later as it was slightly warped, whether from this run away or a past time i dont know

 

[tallcanadian]

So I pulled the carbs off just to check to see if I missed something. There was nothing obvious. I also took the lower unit off to check that as well. It wasn't pushing out too much water so I just wanted to check it all out. Again all looks okay.

I had to turn the red dial on the fuel solenoid to get the fuel flowing. It started after a bit but it didn't run away, however was speeding up. I have the control in neutral, butterflies are closed. It wouldn't shut off every time with the key, I had to choke it out with rags in the carbs. Now I did have a bit of an issue starting it too. It wouldn't turn over at first. I had to mess with the red plug a big and it started to turn over. So I guess I do have an issue after all. So as of right now i have a primer problem and an electrical issue. I will have to tackle. those. I had to turn the red dial on the fuel solenoid to get the fuel slowing. The saga continues.

 

[Bosunsmate]

Electrical problem and primer problem might be conjoined twins, the connection at the red plug not operating the primer.
SPeeding up doesnt sound good, id look at your plugs, might be able to tell if its a general or localised issue

 

[tallcanadian]

Electrical problem and primer problem might be conjoined twins, the connection at the red plug not operating the primer.
SPeeding up doesnt sound good, id look at your plugs, might be able to tell if its a general or localised issue

It's a mess. One thing after another. The plugs are new but are all the same, nothing obvious. Even the old plugs showed no signs of any problem. I've heard from a couple of people that it could be air sucking from somewhere. Possibly crank seals?

I replaced the thermostats but need to pull them out again. It's pumping water but not very much. The engine gets quite hot within a few minutes.

 

[Bosunsmate]

Possibly.
Hot and fast indicates it is running lean.
Any backfiring?
You might want to run it on a hose up the water inlet pipe while you have the waterpump off. That way you can rule out whether its the waterpump causing the overheat or something up stream like a leak into the cooling system. Running lean makes it heat up of course too
Yes more work to do here

 

[tallcanadian]

Possibly.
Hot and fast indicates it is running lean.
Any backfiring?
You might want to run it on a hose up the water inlet pipe while you have the waterpump off. That way you can rule out whether its the waterpump causing the overheat or something up stream like a leak into the cooling system. Running lean makes it heat up of course too
Yes more work to do here

As a matter of fact there were a couple little pops, nothing bad, like hiccups. What are some of the causes of it running lean. I've heard air around the carbs, even crank seals? I appreciate yours and everyone's insights and thoughts. I've got, what it seems like, is a mess on my hands. I didn't run this motor before I started the work on it, maybe I should have.

 

[Bosunsmate]

Its doesnt sound like much of a mess, just need to find whats causing this issue, its probably just one thing thats causing all the bother.
Yes small pops are an indication of it running lean. Air leaks or carb issue.
What i do is i clean all the plugs then i put them back in and i take the lanyard off so that there is no spark and i then turn the engine over using the key in the controls for about four seconds, i then remove the plugs and check they a all wet with fuel. A dry plug will stand out like a sore thumb sometimes, and that shows your problem area.
I also light this fuel with a lighter to check it burns, as quite often it wont when the engine has a problem and this is caused by the wetness being water in the fuel system/cylinder.
So you can try that and you can also try getting back on the horse and running it again and pressing in the choke and seeing what that does

 

[interalian]

Small pops may be accompanied by puffs of smoke around the powerhead. I just found this on a Force 90 - it would pop and puff smoke out the side behind the coilpacks. turned out to be a blown gasket on the center bypass cover. The blown gasket would allow air to be drawn into the crankcase, leaning out the mixture, then making it backfire in the crank case.

 

[tallcanadian]

Question.... I didn't mention this before because I didn't think anything of it, but I unhooked the VRO on this motor. I unplugged the wiring and blocked off where the oil tank hooks unto the gas connector. Will this cause my motor to runaway? Should I do anything else? I took the carbs off again and checked things out. I decided to remover the intake this weekend and ordered in new gaskets. I do know that the PO replaced the reed valves to Boyenson. They look fine as I look at them through the intake but I think I will take a better look and check if the gasket looks normal.

 

[cfauvel]

how about trying an unlit propane torch around the intake manifold and crank case, and between the crank case halves and by the top crank seal and bottom seal?

if you have a leak there the engine will sound different.


And NO plugging the oil inlet to the VRO would NOT make the engine run wild....

 

[ondarvr]

Did he change the jetting when he went with the new reeds, it should be jetted richer, and lean sneezes will destroy the reeds.

 

[cfauvel]

" I do know that the PO replaced the reed valves to Boyenson."

Did he change the jetting when he went the new reeds, it should be jetted richer, and lean sneezes will destroy the reeds.

whoa I missed that tidbit...

did the PO or OP ever have this running right with the new reeds? Or did the OP acquire the boat AFTER the reeds were put on?

OP look up your expected jets for your model and compare them to what you have.