Testing for crankcase bearing seal leak ??

[Pownar]

What is the best way to test the 700 cfi for a leak in the PTO bearing seal?

 

[PaulAnd]

Smoke test will show whats leaking, vaccum test tells you something is leaking

 

[Pownar]

Just smoke a phatty next to the seal while running and I'll see it suck in, eh?

 

[locknload]

with the engine idling mist some carb cleaner around the seal, if the engine changes rpm its leaking.

 

[sled_guy]

What problem are you having? It has been my experience that rarely, if ever, unless something has damaged it visibly, does that seal leak.

sled_guy

 

[Pownar]

2500 miles

No problem, just took the clutch off for cleaning and I noticed more "grime" than usual. It must of happened in the past 500 miles. That is the last time I had the clutch off. It is definitely an oil grime covered in belt dust. There is no drip from the oil though and nothing in the belly pan.

 

[ttyR2]

On chainsaws, I do both a pressure and vacuum test on the crankcase. Sometimes you will have a leak under vac but not pressure, or vice versa. Kind of a pain making up the block plates for the intake and exhaust ports, but it's the only way to be totally sure.

 

[Kraven]

BLOCK-OFF PLUGS

On chainsaws, I do both a pressure and vacuum test on the crankcase. Sometimes you will have a leak under vac but not pressure, or vice versa. Kind of a pain making up the block plates for the intake and exhaust ports, but it's the only way to be totally sure.

BLOCK-OFF PLUGS for PRESSURE TESTING

Regarding block-off plugs, I use the Rubber expandable freeze-plugs for the exhaust Y-pipe and for the one intake boot.

For the one with the air compressor fitting, IF you're in a jam, you can get by with hole-sawing (Approx 1 1/2" depending on carb or Throttle Body diameter) a piece of hard-wood (like oak) if you don't have any scrap 1/4" thick or thicker aluminum laying around, then tap the center hole for 1/4" PIPE thread and thread your air comp fitting into that with some Teflon tape

Hope this helps

 

[mike_s]

Spraying carb cleaner right around the suspect seal is way way easier than fabing up block off plates and plugs and the replacing the seal anyways because you blew it out with too much pressure from your compressor tank.

 

[Kraven]

Spraying carb cleaner right around the suspect seal is way way easier than fabing up block off plates and plugs and the replacing the seal anyways because you blew it out with too much pressure from your compressor tank.

How do you get to spraying the MAG side seal to check that? (You know, that seal behind the thingy with the rope on it and all the wires coming out of the side of the case)

As long as you keep the pressure around 5-10 p.s.i.....................

 

[mike_s]

How do you get to spraying the MAG side seal to check that? (You know, that seal behind the thingy with the rope on it and all the wires coming out of the side of the case)

As long as you keep the pressure around 5-10 p.s.i.....................

Looked as if the OP was asking about the PTO side seal. You know the one just inboard of that angled aluminum pully thingy that spins real fast? come on man, really?

 

[Kraven]

Looked as if the OP was asking about the PTO side seal. You know the one just inboard of that angled aluminum pully thingy that spins real fast? come on man, really?

And after the P.T.O. tests good and you still have a problem, how do you diagnose it?

Look at "tty R2's post",which he is correct about.

My post was in response/support of his post

 

[mike_s]

And after the P.T.O. tests good and you still have a problem, how do you diagnose it?

Look at "tty R2's post",which he is correct about.

My post was in response/support of his post

Go back and re-read all of the OP's posts. He's not having any runability or tuning issues. Only an oily film on the pto side of the crankcase and inner sheave of the clutch. No reason to make this any more complicated than it needs to be for him. Besides, in my 20 years of expiriance, rarely does the mag side seal randomly go bad. Its too well protected by the stator, flywheel and housing. The pto side on the other hand has to deal with all of the belt dust, powder, and the occasional belt explosion which commonly results in threads being wrapped around the crank snout thus destroying the seal. However if you want to spend 4 hours fabing up block off plates and plugs, removing the pipe(s) and carbs (throttle bodies) and then rigging up a regulator so you can spray soapy water on the seals to see if it makes bubbles be my guest. If I were in his position with the question he describes, id just spray some carb cleaner down there and be done with the test in 10 minutes.

 

[diamonddave]

Leave it alone Mike. Before you know it, you'll be told you might wear high heels.

 

[Kraven]

Go back and re-read all of the OP's posts. He's not having any runability or tuning issues. Only an oily film on the pto side of the crankcase and inner sheave of the clutch. No reason to make this any more complicated than it needs to be for him. Besides, in my 20 years of expiriance, rarely does the mag side seal randomly go bad. Its too well protected by the stator, flywheel and housing. The pto side on the other hand has to deal with all of the belt dust, powder, and the occasional belt explosion which commonly results in threads being wrapped around the crank snout thus destroying the seal. However if you want to spend 4 hours fabing up block off plates and plugs, removing the pipe(s) and carbs (throttle bodies) and then rigging up a regulator so you can spray soapy water on the seals to see if it makes bubbles be my guest. If I were in his position with the question he describes, id just spray some carb cleaner down there and be done with the test in 10 minutes.

I'll save you the 4 hours of fab time.

I'll send you the plugs, free of charge, and I'll even tell you where to put them

 

[mike_s]

I'll save you the 4 hours of fab time.

I'll send you the plugs, free of charge, and I'll even tell you where to put them

Smooth. LOL!

 

[Pownar]

Soooooo, do I get the plugs or mike? I think I'll spray some carb cleaner or some smoke and see what happens. From there I'll probably go with the plugs/ pressure test. Thanks for all the help guys.