Spare saves runaway yamaha

B

bksah2

Junior Member
SPARE can put some insight on what caused the out of control RPMs on the yamaha and what you did to stop it ...I have heard of this happening before,, im glad he was not in gear heading back to the dock when it happen
 
At the time he mentioned the only thing that he noticed was that a hose was hung up some how on the linkage (couldnt see what hose he was pointing to).....I would like to know how the ignition doesnt cut it off. In our conversation at the bar later we wondered what would have happened if Dave wasnt standing righ there... somebody mentioned (maybe Lee) about pulling the kill switch lanyard . Would be interested to know if that would have shut it down.

The only thing I could do at the time was stand there and look like this:

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I thought you were in for a meltdown. Never seen that one before. Anxious moments. I bet you were about to drop a pantload right about then.
 
Either One Fits.
Actually crap in pants Due to replacement powerhead.

And to think the manufacturers really don't want the owners to exceed 1500 RPM in neutral due to the chance of chatter on the rod bearings without a load.:head:
 
I've talked to several people about it. best idea we could come up with is once the engine was at a higher rpm( it ws at fast high idle) with no load, it started dieseling. Cutting the engine off(same as pulling the kill switch) would just short out the ignition, but at this point it was running with out spark, kinda like the top fuelers do when the ignition fails. the engine kept getting to higher rpm, i was fumbling with the throttle, couldn't figure anything out, so i grabbed the fuel line and kinked it closed. I kept fiddling with the linkages, trying to get the rpm down, when it finally started slowing down as it used up the fuel in the bowls. I really don't know exactly what stopped it, I was doing three or four things at one time when it started slowing down. i never seen one do it before.
 
I don't think that would have anything to do with it unless the tank vent was clogged. The only other thing that concerned me was afterwards, the primer bulb would not prime up hard with the engine off. It may have been drawing fuel thru the venst froma stuck needle or posible thru the fuel pump diaphrams
 
I had an old Kawasaki jet ski that would do that when being flushed on the trailer with no load. I had to cut the fuel to get the dang thing to quit. It would idle up pretty high and pretty much scare the crap out of anyone nearby.
 
spareparts said:
I don't think that would have anything to do with it unless the tank vent was clogged. The only other thing that concerned me was afterwards, the primer bulb would not prime up hard with the engine off. It may have been drawing fuel thru the venst froma stuck needle or posible thru the fuel pump diaphrams
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This sounds like a pretty RARE occurance...but it might point out a need to install an easy to get to, fuel shut-off in the line...

As you had to kink the line to kill it, wonder if the line has now been compromised and needs to be replaced...
 
spareparts said:
I don't think that would have anything to do with it unless the tank vent was clogged. The only other thing that concerned me was afterwards, the primer bulb would not prime up hard with the engine off. It may have been drawing fuel thru the venst froma stuck needle or posible thru the fuel pump diaphrams
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There is a good possibility the vent was "clogged" so to speak...I had just filled at the gas station prior to launching that day and thought I had way less fuel in the tank than actually was.....had gas spittin' out the vent when I stopped filling. How does that come into play?
 
RWilson, I think Spare was trying to say that a plugged fuel tank vent coupled with the engine sucking fuel out of the tank would create a vacuum and prevent the primer ball from functioning properly.
I want to hear more on the dieseling theory. What would get hot enough in such a short timeframe to cause it, carbon, the spark plug itself? AND Would a lean run condition cause it to rev up worse? I know when I run my 2-strokes out of fuel the RPM's pick up just before they shut off.
Could the motor have been choked off by pushing the key in?
What a crazy thing. If that happened in gear, in Shem Creek, you wouldn't be able to take it out of gear and the results would have been interesting to say the least.
 
bradford said:
I had an old Kawasaki jet ski that would do that when being flushed on the trailer with no load. I had to cut the fuel to get the dang thing to quit. It would idle up pretty high and pretty much scare the crap out of anyone nearby.
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i had a Kaw 550 Standup that did that right often when the timing was off, i aways killed it but covering the carb so it got no air, it turned out the timing was off by 4* doesn't sound like much but it fixed it once timing was set.
 
Do you agree that if it were caught early enough it could have been avoided? There was noone in the boat at the time the motor started to rev up.
 
Actually I had just pulled it in close enough to board when it started to rev up, and Rob was on pretty quick, just before it went bezerk and shut it down but it had no effect.
Thats when up in the sky what did I see? A bird, a plane, no, it's super Dave.
 
willy said:
Actually I had just pulled it in close enough to board when it started to rev up, and Rob was on pretty quick, just before it went bezerk and shut it down but it had no effect.
Thats when up in the sky what did I see? A bird, a plane, no, it's super Dave.
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As it started to rev up, I thought it was fuel starved as Ridge mentioned and that it was about to shut down...but when it kept building RPMs w/nobody onboard, I started clickin' the shutter, cuz I was pretty sure SOMETHING was gonna happen and I wanted to document it, good or bad...glad it turned out good...there are a couple of shots in the sequence I didn't post..if anybody thinks they might be helpful in figuring out just what happened, lemme know and I'll post 'em all up...
 
reelapeelin said:
As it started to rev up, I thought it was fuel starved as Ridge mentioned and that it was about to shut down...but when it kept building RPMs w/nobody onboard, I started clickin' the shutter, cuz I was pretty sure SOMETHING was gonna happen and I wanted to document it, good or bad...glad it turned out good...there are a couple of shots in the sequence I didn't post..if anybody thinks they might be helpful in figuring out just what happened, lemme know and I'll post 'em all up...
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I was going to comment about your pic sequence....here's my engine ready to blow and there's Reel playing Jimmy Olsen over there....click, click, click. I had no idea you were taking pics all along but it made for an awesome set of pics there.....Is that what you always do in times of emergency.....hey let me get this camera rollin!!:fam:
 
RWilson2526 said:
I was going to comment about your pic sequence....here's my engine ready to blow and there's Reel playing Jimmy Olsen over there....click, click, click. I had no idea you were taking pics all along but it made for an awesome set of pics there.....Is that what you always do in times of emergency.....hey let me get this camera rollin!!:fam:
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It started happening pretty fast...and I was too far away to get to it and do anything...and wouldn't have known what to do had I been in the boat...figured pics better than nothing...The right man got to it first no doubt...
 
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