06-03-2008, 02:11 PM #1
this is what a lean 3 hour piston looks like
I replaced this 3rd piston in a friends ski last october, we thought we had the problem taken care of, I guess not, we took it out this past sunday for the first time since the new piston, it was hard to start with a couple of backfires. I thought it was due to bad fuel, he had it sitting with a 1/8th tank and stabil since october, he filled it up with premium before we went out. It started and ran with some missing, still thought it was bad fuel.. ran it for about half tank, then it seized, had to ride it back for about 20 minutes..got it home and checked compression 110, 110, 0...Whooops...
the other two cylinders look lean, all black with little, size of a pinkie nail, washout marks...could not feel any particles in the other cylinders and no debri in the crankcase.
the ski is stock with the exception of a stingerII pipe, Im going to check the carbs and all the fuel lines, the check valve on the tank, and the reeds before i put it back together...
anything you guys can think of what else to check???
06-03-2008, 02:17 PM #2
- Join Date
- May 2008
if its for a 1200 pv motor i have a set of carbs like new if you dont want to rebuild them
06-03-2008, 03:03 PM #3
Super lean - it melted right above the exhaust port.
06-04-2008, 08:55 PM #4
- Join Date
- Aug 2006
Maybe you have a bad rear crank seal letting air in, that is a serious lean seizure. I'd do a leak test for sure when done.
06-04-2008, 09:29 PM #5
If your planning on just replacing the cylinder and piston and not tearing the bottom end apart your asking for more trouble down the road. Eventhough it may not look like theres anything on the crank or in the cases there is. It's fine bits of metal that will destroy then engine with time.
If it were me I would tear the whole motor apart clean everythign very very well and assemble with the crank seals and new gaskets. Then that way your know it's right and you won't have to worry at all.
Al so like some others have said once the motor is together do a pressure test to make sure there are no air leaks.
Some may not feel the same about taking it completely apart but this is just my .02!
06-04-2008, 10:20 PM #6
06-05-2008, 08:23 AM #7
Im going to split the cases this weekend and clean them out, while the engine is out i will be going thru the entire fuel system from the flapper on the pickup to the filters in the carbs..
I am also going to enrichen the high speed on the third carb...
and i will pressure check the engine before it go back in the ski...
Does anybody have the link to where fercho shows how to make the pressure gauge???
06-05-2008, 08:37 AM #8
What is done to the carbs? if you are running stock jetting on them expect the same results. They need to be jetted properly for the stinger.
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