657X FRESH REBUILD WON'T START/STAY RUNNING

[Theseadood]

94 XP with freshly built topend, overbore with SBT pistons. Hooked the hose up and tried to start it for the first time and the engine will not start/ stay running under its own power. Seems to want to stay running when the starter is held. Anyone have any suggestions or ideas? thanks

 

[mikidymac]

You didn't have the hose on with the engine not running did you?

 

[Theseadood]

We turned the hose on and then tried to start it

 

[Theseadood]

What sort of damage could that have done? We tried starting it quite a few times just now.

 

[mikidymac]

You will flood the engine, cylinders and crankcase with water. You need to pull the sparkplugs and see if water shoots out when cranking.

If it has water in the cylinders you need to clear it out and get the engine running immediately or you will rust the bearings and cylinders.

Never run the water to a ski with the engine off.

There is really no reason to run on the hose unless you are flushing out salt water or the cooling system.

Just make sure the ski runs then put it in the lake as the drive system will not be cooled by the hose and there is no load on the engine which isn't good on a new engine..

 

[Theseadood]

Okay, there is no water coming from the plug holes but they do look wet. So just try to get it started? Or do we need to make sure there’s absolutely no water in there? Could it be MPEM?

 

[Theseadood]

Drained all water as best we could, removed the rotary valve cover and applied oil in there even, put everything back together, but still no avail. Throttle works for a moment but not without punching the starter a time or two.

 

[mikidymac]

You need compression, fuel and spark.

Did you rebuild the carbs using all new Genuine Mikuni parts?
Did you leak down test the engine?
Did you check compression?