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So I just wanted to hear other peoples opinion on my leak down results for my new motor. Keep in mind I can not hear any rushing air and spent roughly an hour trying to track down a potential leak with soapy water in a spray bottle.

Little background, sled is a 06 800 P-Tek. The motor is new and fresh all around, pto cylinder, crank, pistons/ring etc, oil pump and y pipe all new. Followed the procedure and this is what I have gotten so far.

Pump up system to 5 PSI, time it for 5 minutes and it leaks roughly 0.5PSI.

Left test on and it continued to bleed slowly down to 3PSI after 17 minutes.

Test was done with the PTO elbow off. Will try with it on this Saturday.

Any ideas on where I should be spraying the soapy water? Went through the exhaust, carb boots, base gasket, oil pump and spark plugs. Initially one bolt was loose on the exhaust but I only got a slight bubble every 20 seconds, and same with a spark plug. Other than that I can not hear or find anything.

Just a little hesitant right now to finish everything up with the slight leak.

Thanks :)
 

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Make sure spark plugs are tight and maybe try testing each side with the y pipe off. I use a square piece of plexi with butyl tape to seal it. Used the y pipe as a template to drill the holes, then added a hose fitting in the center for my pump.
 

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Doesn't sound bad to me is your impulse line closed good probably slow leak at exhaust
That impulse line gets me a lot.. even with gas line on the jaws.. lol.

Have you tried it with the cap on the pto?

If you really want to know if its your mag seal.. you will have to remove the y-pipe and put block off plates and leaktest individually or remove the flywheel.

You could also 5lb leaktest at the center cavity nipple. It will take longer for pressure to drop with oil in it.

Also take the heat shields off the y-pipe and soap up the weld at the y.

The manual says like 3 minutes i think.. I go with ten or 15 minutes.. if no drop.. I put it back together :)
 

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Discussion Starter · #6 ·
Thanks everyone!

I will try with the PTO cap on to see if there is any difference. I also am planning on using some silicone on the carb boots (where they mate the cylinder) and pinching the impulse line with a set of needle nose vise grips (right now I have it plugged with a solid plug).

I sure hope its not the MAG seal, the crank is new but you never know I guess.

Cheers
 

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I also am planning on using some silicone on the carb boots (where they mate the cylinder)

Gasoline and silicone don't mix. I would refrain from doing that. Needs to me a mechanical seal, silicone will always fail given time.

With the .5 lb loss in five min's I say your fine. That small loss can usually be tracked down to your pressure device, lines or block off devices.
 
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