Thread: 372xp Compression??

Hello all,

Registered a bit ago and have been lurking around and reading all the GREAT information on Arborist site!

Now I have a question of my own. I have a fairly new(Purchased July 09') 372xp that has had about 3-4 tanks of fuel through it. Since the first tank I have been running XP mix w/93 octane fuel a bit under 50:1. 1.8 gallons of fuel for a 2 gallon mix.

On Saturday I decided to do a compression test on it. Tried 2 different gauges and both read 90 psi cold and bit less hot! Both gauges have a shrader valve.
From what I have been reading on AS it should be between 140-150 psi.

My Question is, Do I need to run the saw more in order to get everything to seat? I have called all the Husky dealers around and none of them seem to be of any help at all! It should still be under warranty but I honestly don't trust any of the dealers around here to do the right thing.

I know this is a great reason to put a BB kit on it but I was planning on keeping it stock for a few years!

Thanks for any help and information you can give me!!

Mike

Is the Schrader valve at the very tip of the hose where it screws into the cylinder? I doubt it would even run with only 90 PSI.

You might want to pull that starter rope more than once.......

And you might want to make sure the compression release is closed and the throttle is held wide open.

Thank you Sir!! I will check. What would make it not run with only 90psi. Would there not be enough compression for the cylinder to fire?

Is the a compression gauge you would recommend for saws?

Sorry for all the ?? This is all new to me!

Don't take it personal but

I Swear To God I'm Going To Woodinsville!

Comin to join yah Andy.........

A tester with the valve at the gauge will only give a reading of approx this.
It needs to be a gauge with the valve at the tip as Brad stated and the procedure as Pes stated.

From my experience, I give the saw five pulls with the cold start throttle opener on, I get 160PSI on my 181 & 630, 170PSI on the 009, 175PSI on the 345 and 175PSI on my 254.

Maximum I have had is 200PSI on the 630 with no base gasket.

Doing this on a dry non fueled engine will lower the compression, if there is fuel oil mix in the cylinder, this will increase the compression.

90PSI is very low and would get a second opinion or test another saw before stripping it down.

Spud

Originally Posted by ridgerunner

Thank you Sir!! I will check. What would make it not run with only 90psi. Would there not be enough compression for the cylinder to fire?

Is the a compression gauge you would recommend for saws?

Here's a piston that had about 85 psi...the ring is completely smashed down and aluminum is smeared over the ring slot, preventing the ring from being able to float around the slot and keep the seal good on the cylinder wall.



I use one of these Lisle gauges...you can buy them in most auto parts stores, or on Amazon. I posted a link last week that was about $30 on Amazon, but I can't find it now so someone must have bought the last one who saw that post possibly.