Engine rebuild fail

[FlushyStr8er]

Hey guys,

I just gave my first try on an engine rebuild - and it fail! The engine broke after just 1.3 hrs...
After rebuild i had 145psi on both cylinders. Rebuilt the carbs too. The one of #2 was very dirty and I wasn't able to loose the needle seat, without destroying the screw - so I let it in it's place.
It started just with useing the primer, thought it's the idle rpm I hadn't adjusted, yet. I noticed already that the cylinder #2 run a bit to lean, so I stopped the first day after 0,75 hrs break in. Proofed the carb settings and switched from riva air filters back to the original one, to get it running richer.
Gave it another try for about 10-20min... it sounded way to rich and was running bad. I decided to stopp again.
Back home I took off the exhaust again to check everything. I adjusted the carbs again and increased the idle speed. Gave it a try... it started but sounded bad.
I checked the compression angain: #1=120psi #2= almost 0












I don't know what I did wrong!
I choosed the right fuel mixture 1:32
I was even driving carefully cause of breaking in.

I thought already that the carburetor of #2 is just broken... but on the other hand, I replaced all parts. Even if the needle would be blocking in the seat (I couldn't remove) it should have just run to rich, or am I wrong?

This night I thought about my crankshaft seals... could it be possible that I mixed 'em up?
I orientated to those of the crank I replaced. (just bought the ski)
If I'm right, you just can place them at one spot - theya will fit just in one way. Or don't they?
What about my outer crank seal at coupler - is it right, the way it's placed?
Or did I do it wrong and produced an air leak?



Thanks already forwarding for your help!!!

[Technical Support]

Re: Engine rebuild fail

Looks like the rear seal is in correct, did you leave debris in the exhaust and it got sucked back into the cylinder? Did you use case sealant on the case halves and base gaskets? Maybe still carb related 32:1 should be fine.

[FlushyStr8er]

Re: Engine rebuild fail

Looks like the rear seal is in correct, did you leave debris in the exhaust and it got sucked back into the cylinder? Did you use case sealant on the case halves and base gaskets? Maybe still carb related 32:1 should be fine.

Thanks for the fast reply!

****, I hoped it was an airleak through the crank seals... - but on the other hand glad I did it right.
I used a whole new gasket kit (bought it at yours), new reed and power valves, new/ rebuild crank, new coated cylinders and two carb rebuild kits. So everything is new.
For the crank case I used Petec sealant - even asked one of their applications engineers to get sure I use the right one.
For the exhaust and the PV cases I used sealent besides the gaskets too. Cooling was working perfect - tested with my hands exhaust and head after and during test drive.
Even had a "pro" giving it a test drive too the first time. He told me to switch back to the OE airfilter to get it running richer. He had the feeling it's running lean during riding turns and almost dies. He was wondering why I had to use the primer almost every time... (I thought it's the wrong idle speed).
I cleaned every part with compressed air and with a special work cleaner LIQUI MOLY - Motor Oils, Additives, Car Care - Products - Schnell-Reiniger
The oil was TC-W III LIQUI MOLY - Motor Oils, Additives, Car Care - Products - Formula Racing Outboard Motoroil
That's why I thought it might be the one carb... - don't you think so? I was wondering why one is working as supposed and I just had that problem on the #2 cylinder.
When the engine broke the first time, it was the same cylinder that got destroyed. I contacted the seller (had the ski just 4-5 times on the water) when it died. He replaced the crank with an HotRods, but just used one base gasket. The guy, who coated my cylinders told me, that the head was once modified by him, and I should take two base gaskets to ensure the pinch point size. He also told me that the pump of the carbs are deactivated and that there are other jets in there to be able to run 1:60 (but I don't like to run it that lean, cause I am affraid that will shorten the life time of my engine). He said to rich fuel can cause a lean mixture through those new needles he put in... is that true? Cant imagine.

When I built the engine I even did a leak down test and sprayed soap water on everything. The onliest points of leaks were the PV cases and the intake + exhaust gaskets I built myself for the test. So I opened the PV cases again and used sealant next to the gaskets.

The other reason I assume for this failure:

When I replaced the new Power Valves, they fit a bit tight (right position, not upside down). I thought they might have fined down some of that new nicasil coat. - But I asked the guy who coated 'em, and he said it should be almost impossible cause the corners of that valve slides are rounded. PVs look ok too.

[Technical Support]

Re: Engine rebuild fail

Sounds like the issue is in the carb, I would replace the carbs or at minimum put it all back to stock.