2000 sportster le no propulsion and engine runaway.

[Stinkeyechester]

Hey guys, this looks like an awesome forum. My problem is this, I had my boat out yesterday, going along at just under wot towing my brother on a tube when BAM! I lost propulsion and engine started reving to at least 7 or 8 grand. Pulled lanyard and she continued to rev until I choked it out. Now, soon as shes started she revs right up to 7 grand. I'm not leaning towards air leak just because of how quick it happened and the loss of propulsion?Also the engine sounded different, like less of a load on it. I'm thinking something let go in pto or shaft. My question is what is causing the runaway as soon as it is started? Is there that much of a load on the impeller that a broken shaft would cause the engine to rev so high as to cause a runaway? Also, how freely should the shaft at the aft of the engine spin by hand? I removed the cover with the two plastic wing nuts and reached in and spun it fairly freely. Any help is greatly appreciated.

 

[Coastiejoe]

I agree with a shaft/PTO issue.

Unless the throttle cable was affected at the same time I am not sure what would cause a continuos max RPM issue.

 

[Stinkeyechester]

Throttle cable is working as it should as far as I can see.

 

[Seadoobuddy]

I thought the PTO shouldn't spin freely if the plugs are still in. Shouldn't it be tough to spin by hand that way?

 

[Guest_User]

typically no load on the engine and it can rev out to 3000-3300 rpm with the sticks at idle position.
now if you were motoring along and 1/2-3/4 throttle and the splines/shaft let go, the engine would sceam possibly creating a hot spot in the combustion chamber/head dome or piston crown and making the engine run away from that fire source. it doesnt take much and these engines don`t like a runaway...

I would bet that you lost an impeller (splines) and or drive shaft. This could also be from the engine being to far forward and not enough spline engagement...

you won`t know for sure until you start disassembling the drive system...

 

[Dr Honda]

typically no load on the engine and it can rev out to 3000-3300 rpm with the sticks at idle position.
now if you were motoring along and 1/2-3/4 throttle and the splines/shaft let go, the engine would sceam possibly creating a hot spot in the combustion chamber/head dome or piston crown and making the engine run away from that fire source. it doesnt take much and these engines don`t like a runaway...

I would bet that you lost an impeller (splines) and or drive shaft. This could also be from the engine being to far forward and not enough spline engagement...

you won`t know for sure until you start disassembling the drive system...

Ummmm...


Yep. What he said.

 

[Stinkeyechester]

My thoughts exactly, but im wondering why she's still revving right up when started. I've started it twice since the "event" and the first time revved right to max, second time it idled a bit then I slightly touched the throttle and she revved right up again. Gonna pull pump and shaft out tomorrow. Any more ideas would be great. Thanks.

 

[Guest_User]

My thoughts exactly, but im wondering why she's still revving right up when started. I've started it twice since the "event" and the first time revved right to max, second time it idled a bit then I slightly touched the throttle and she revved right up again. Gonna pull pump and shaft out tomorrow. Any more ideas would be great. Thanks.

find the source of the shaft issue first, them you might also find your throttle is not returning quickly or to the idle stop on the carb.

what engine is in this boat, and any history would be helpful for others to reply...

worse case is to perform a pressure test to see if you have a seal that is sucking in air...

 

[howie099]

Airleak or stuck throtle plate causing the high reving. Airleak is bad you will loose the eninge pretty quick running lean.

 

[Sportster-2001-951C-Stock]

These engines run away pretty easily, some report out of water idle over 3000 RPM is all it takes to quickly make 8k. One hot mama!

I vote for no-load runaway and make sure my choke linkage is working properly. Each "PTO-stripped!" post I see, I immediately run outside with grease gun in hand.

 

[Stinkeyechester]

Update, just looked in engine compartment, she's now filled with oil mixed with water in the bilge. This is starting to look worse every minute.

 

[ericbesso]

thats never good. hope its the best case scenario for u man

 

[Stinkeyechester]

Thanks, I pulled off pump, shaft and pto today. Splines were well worn on both shaft and pto. Rubber bumper was missing from end of shaft, can't find source of oil leak. Now I'm on the hunt for parts. My local dealer charges on average between a 100 to 200 percent markup on parts compared to ordering online!