A real conundrum!

snodawg 315 · Post by **snodawg 315** » Fri Jan 09, 2009 11:21 pm

I am voting for crank center seal. I know you said that you replaced seals, but I'm guessing that the center seal was not changed and even if it was, still my vote.

colt250ss · Post by **colt250ss** » Sat Jan 10, 2009 11:10 am

Thanks for all of the suggestions guys! Here is an update. We pulled the motor completely down. The outer seals are indeed new. However, what is the deal with the center seal? We are thinking that this is the issue. How does it work? Is it some kind of Hydro Seal principle? How does one change one, and are they even available? Everything else looks fine, and the crank checked out as well. Thanks so much for all of the help, it is greatly appreciated by all of us. Thanks again, and we will keep everyone in the loop. Forrest

That Girl Racing · Post by **That Girl Racing** » Sat Jan 10, 2009 3:47 pm

Heres one. Gasket between mag cylinder and intake manifold.

Rodimus Prime · Post by **Rodimus Prime** » Sat Jan 10, 2009 9:18 pm

Kohler crank seal in center is oddball 2 rubber seals back to back cant offhand remember the seal numbers. Someone might have found a different seal for it in middle over the years if you see a aluminum center between the two inner bearings then it was replaced with the defection type. ( its doable not common but doable )

Hawkeye · Post by **Hawkeye** » Mon Jan 12, 2009 11:58 am

So I fear, I am having the same problem. Although, mine appears to be intermittent. I previously thought it was a fuel delivery issue, but after rebuilding the fuel pump, replacing all the fuel lines, I still again can not get it to advance past idle. When I picked it up I had full throttle range, then it stopped and only would idle, I pulled carb, cleaned it and replaced fuel lines and it ran again although would not make full power (strong til you went past about 66% throttle). Further examination showed bubbles in line between carb and pump, so rebuilt fuel pump (now I understand that air in the line is normal) after rebuilding fuel pump I'm back to won't throttle up. So trying to determine where this center seal is... I don't believe their is anything left to check on the fuel delivery side. I have had very strong spark the entire time.

Attached is the crank, bearing and seal exploded parts view, which part is the center seal? I would appreciate any help.

Thanks.

Attachments:

Spitfire_Crank_Bearings_Seals.gif (7.7 KB)

Rodimus Prime · Post by **Rodimus Prime** » Mon Jan 12, 2009 1:18 pm

In pic you see the two inner bearings right in center is center seal.

Wont rev up common problems, cdi, stator shorted, crank out of alignment, bad sparkplug, fuel pump or fuel pump impulse line leaking, bad clutch, bad piston, air leak due too seals or gaskets causing non firing on one side of engine, mousenest in intake/crankcase/exhaust pipe, rev limiter switch out of adjustment or limiter not functioning.

most of that is easy too check disconnect belt, exhaust pipe, impulse line and plug inlet, disconnect engine harness from limiter, change plugs use known good cdi, use ohmeter to check stator, check seal and gasket areas with spray while engine idling. do them in sequence most times youll find the problem in 5 mins or less.

Other things i have found over years, fresh engine rebuild with stuck rings/broken rings/ wrong piston( found one missing rings but still idled somehow) gaskets not sealed is another good one people have this thing that a brand new gasket will seal itself on a old aluminum engine. Sparkplug caps replaced with resistor type caps (not good idea on old cdi) seen cranks with bearings shot on conrod.

Center seal is semi hard starting and engine surges during operation. Also wont have any topend power but still does accelerate.

Bad cranks pto side wont run.