Compression Issues

[BigRed96]

Hey Everyone, my issues are with two of my saws. A MS290 I built using a Hutzl 390 kit and Caber rings, and a 025 that was given to me. Both only blow 130 on my compression gauge and I believe it to be correct. However, both saws run and cut great. The 390 has large felling dawgs on it and pulls a 24" bar. I would say I lean on this saw pretty hard. The 025 is the same way, runs and cuts great. Normally I wouldn't care about the low numbers but I want to post both saws for sale in the sale section. I don't want people to think I'm lying when I tell them they run great and then give them compression numbers. Here is a video of the 390 in some ash, what do you all think?

 

[Stihlbro]

I would try a different compression tester. Borrow one if needed. Even if you have a new one.

You can take a air compressor and kinda spot check your gauge if you have a regulator. Check in 10 lb increments.

Final thoughts, put a few drops of two stroke oil in the cylinder and recheck compression. The would qualify ring seal.

 

[BigRed96]

I have checked my to Husky 51's and they blow 150 and 160 with this tester so I think it probably right. I will see if I can borrow one though and check again. I will try the two stroke oil as well. Thanks for the reply.

 

[jmssaws]

If you take the tester firmly and throw it in the trash your problem will be over.

 

[TJ the Chainsaw Mechanic]

Compression is over rated.

Low compression? Just add some water. Bring the numbers way up.

 

[drf256]

Agree that your tester may be the culprit here.

GLWS.

 

[paragonbuilder]

I've got a husky 350 here with a muffler mod that blows 100psi. If I checked it before running I wouldn't have thought it would start. And yet at the NY gtg, running as a baseline against 4 ported saws, it took 3rd place.
That taught me something.
And it looks like the saw runs great! I wouldn't worry about it.


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[paragonbuilder]

Those saws may be a hard sell on this site with us crazy performance minded goons. I bet they would sell great for good money on Craigslist this time of year.


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[67L36Driver]

This Craftsman/Poulan starts easy, runs and cuts great.

The cylinder, piston and rings look near new.

Pumps 125 on my Sears gauge. Surprised the hell out of me.

The same gauge reads 170 on my Olympyk.

Both with dry cylinder after run and cooled down.

 

[RI Chevy]

What do brand new saws come with as far as compression goes?

 

[paragonbuilder]

What do brand new saws come with as far as compression goes?

All over the road Jeff. 100ish is normal on a husky 350. A lot of dolmars are blowing 200 out the door.


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[BigRed96]

Cool, thanks for all replies. I was in fact going to post the saws on this site. I have them on Craigslist right now and haven't had any bites yet.

 

[paragonbuilder]

Cool, thanks for all replies. I was in fact going to post the saws on this site. I have them on Craigslist right now and haven't had any bites yet.

Cool. If you are a member of AS post them there too. Seems saws go for a little more there from what I've seen.


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[paragonbuilder]

Cool, thanks for all replies. I was in fact going to post the saws on this site. I have them on Craigslist right now and haven't had any bites yet.

Do you have an upgrade in your sights????


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[jockeydeuce]

All over the road Jeff. 100ish is normal on a husky 350. A lot of dolmars are blowing 200 out the door.


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Funny (or not so funny) story. ....I put together a 2150 Jonsered a little while ago and wasn't familiar with these saws. Swapped two perfect looking top ends and couldn't seem to get more than 115 on the gauge. ...Finally found out that's just the nature of the beast and moved on...lol

 

[jake wells]

i got engines that blow 90 psi and run great but yet that is what they spec.
it is just the nature of some engines.

 

[Jon1212]

How many tanks do you have through them? Doesn't compression generally go up over use time following a rebuild?

 

[BigRed96]

Do you have an upgrade in your sights????


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Yes, I would like to find a blown up 044/440 to rebuild. The 390 weights about the same as a 044/440 but the 044/440 has more power to move a bigger bar and chain. This would be my main felling/firewood saw.

 

[BigRed96]

How many tanks do you have through them? Doesn't compression generally go up over use time following a rebuild?

The 025 was given to me with some issues but did run so I haven't been inside of it. The 390 has somewhere between 30-50 tanks through it. After building the 390 I checked compression and it was 128, so it came up after break-in but only 2 pounds.

 

[RI Chevy]

I always thought 150 psi was low. Lol