runaway engine

[gsxr800]

Today my ski started to idle at around 2000 rpm in the water. otherwise it seemed to be running ok. I tried to turn the idle adjustment down some but didn't make much difference. Now its been running fine since may when i put in a new sbt motor in it. So I took it out of the water and started it up and it raced out of control. I had to pull choke to stop it. let me tell you what has been done to the ski with new motor (951)

1. all new fuel lines
2. fuel selector was clean.
3. rebuilt carbs with all internals replaced including new fuel filters.
4. compression was 135 and 132 (As of last week)
5. pressure tested rave pulse line no leaks.

Also today I see what looks to be oil on the case where the engine number is stamped. Could it be an air leak at the base gasket of the cylinders?

[dsolie]

Re: runaway engine

Turn the idle back up a bit, see if that changes it. Sounds like you are just a hair lean on the low speed screws.

The 951's are notorious for running away on the trailer, when nothing is even wrong with them lol..

[gsxr800]

Re: runaway engine

Its been running fine since the end of may when I put it back together. So thats why I was concerned and was hesitant about playing with settings when it was running so good.

[gsxr800]

Re: runaway engine

So I got a chance to re torque head bolts. and started it up and adjusted the low speed screws and idle so its around 2800 out of water. It ran fine. looked at the plugs again and mag plug electrode was more dry than the pto side electrode. So I backed off on the pto side adjuster about an 1/8. Also compression tested again. 135 both cylinders. I just realized I torqued the bolts to 35 instead of 25lbs! Is that going to cause a problem? I guess that explains why most of them turned about a 1/4 turn! I just can't win!

[dsolie]

Re: runaway engine

You should be fine on the torque....I usually torque all my 951's to 30 anyhow

[gsxr800]

Re: runaway engine

Thanks!

[troyg1130]

Re: runaway engine

sometimes the lever under the carbs get stuck and make the ski run out of controle ...where the throtel cable connects to the carbs make sure their always oiled theay get stuck in open position happend a couple times...

[gsxr800]

Re: runaway engine

well i got a chance to explore the motor and found the base gasket blown out on the mag side cylinder. What is the reason for this? Is there a quick fix for it or am i pulling the motor again? I am really starting to hate this 951!

[skisol]

Re: runaway engine

You started this topic telling that since May you installed the SBT engine, I guess that was 2008, so if you purchased that in May of 08 you should still have warranty on it, if so contact SBT and you probably end up pulling the engine and have to send it back to them.

[hhiibel]

no quick fix for base gasket failure.

you say it's an SBT motor? If so, contact them. Does SBT instruct you to retorque the head?

[gsxr800]

Re: runaway engine

well this was a cylinder exchange kit that i did this time around. So I assembled the motor. But from what i have read I'm not the only one out there that has had or has this problem. What causes it? is there a quick fix? or am I taking the motor back out again?

[Technical Support]

Re: runaway engine

No we dont tell you to re-torque.

[dsolie]

Re: runaway engine

If it's just a cyl exchange then you possibly installed the base gasket incorrectly, or it wasn't torqued to spec during your initial install.

Pop the cyl off and throw another base gasket on it... Torque it back down and see how she goes. On your ski, you can do the job in the ski, it's just a little of a pain.

[gsxr800]

Re: runaway engine

If it's just a cyl exchange then you possibly installed the base gasket incorrectly, or it wasn't torqued to spec during your initial install.

Pop the cyl off and throw another base gasket on it... Torque it back down and see how she goes. On your ski, you can do the job in the ski, it's just a little of a pain.

How do you install it incorrectly? It was torqued to spec during the install. How do you get the cylinder off with out pulling the motor? I could not find a way to get the cylinder off while in the ski.

[dsolie]

Re: runaway engine

It get's pinched, folded a little.. I have seen people spin the crank by hand while the cyls were on and not bolted down.. This lifts the cyl up and the piston skirt can snag the gasket etc..

Since I was not there, I have no clue but to guess. Another option would be the cyl base needs to be decked, as it's not flat... A machine shop can check that for you.

I always install my base gaskets with "Three Bond 1211".. A little bit goes a long way to ensure a little extra protection.

In order to remove and re-install the cyl in the ski, you have to remove the studs holding the cyl in place. You have to double-nut the studs so you can un-screw them. If they still have the small o-rings in each stud, it's even more of a pain in the arse. Once all the studs are out, you can just pull the cyl up, and out. Re-installing will take 2 people (or more). Because you have to install the cyl at an angle and get the pistons on correctly..

I have done it.. it's a pain.. I prefer to pull the motor, but then the pipe etc has to come all out again, also a pain sometimes.