Blown Head Gasket?

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  #1  
Old 01-18-10, 06:34 PM
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Blown Head Gasket?

I have a leaf blower that seems to be getting fuel and spark fine. Its only a year old or so. It won't even sputter. I did a compression test and got 60psi. So I took the jug off and everything looks great and well lubricated. I put it back together and did another compression test. I got 65psi this time. Is this a tell tale sign that there is a blown head gasket? Thanks in advance!
 
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  #2  
Old 01-19-10, 12:40 AM
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A hand-held 2-stroke leaf blower shouldn't have a head gasket. Is this a 4-stroke or a large wheeled blower?

Sounds like a stuck ring and/or scored piston and cylinder.
 
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Old 01-19-10, 05:58 AM
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Originally Posted by cheese View Post
A hand-held 2-stroke leaf blower shouldn't have a head gasket. Is this a 4-stroke or a large wheeled blower?

Sounds like a stuck ring and/or scored piston and cylinder.
My hand held 2 cycle has a gasket. It looks like an O-ring that has an overall square shape but a round cross section. It fits in a groove in the crankcase.

Mine quit a month or so ago due to low compression. In my case it was a scored piston and head. Replaced both and after a little carburettor tweaking, it runs quite well again.
 
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Old 01-19-10, 06:06 AM
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If you suspect it is leaking at the joint between the cylinder head and crankcase you might try anerobic sealant or so called "Porsche Glue". The sealant is placed on clean and smooth metal surfaces that bolt up. The lack of oxygen causes the sealant to harden and seal. The material that oozes out does not. The material that oozes into the motor is dissolved in the engine with no ill effect. It is impervious to petroleum and withstands high temperature. It is used in the automobile industry and is what is called for for sealing balance shaft housings that are filled with very hot engine oil. Along with 944 balance shaft housings, it is also what is used in sealing 911 engine halves together. Made by Loctite Corp.
 
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Old 01-19-10, 07:30 AM
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The piston and ring looked great. There was plenty of lubrication (black oily residue from two stroke gas.) Where else could I be losing compression? Shouldn't I be seeing around 100 psi?
 
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Old 01-19-10, 07:59 AM
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I did not have a compression gauge when I noticed low compression. What I did was remove the muffler so I can see the side of the piston. I squirted motor oil on the piston then slowly pulled the starter cord. I could see bubbles as the comressed air slipped by the piston. It was at that time that I removed the head and saw the scoring.

I think the compression pressure should be somewhere in that neighborhood but I do not know for sure.
 
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Old 01-19-10, 05:53 PM
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100 psi, yes. Still want to know what we're even talking about.

The 2 stroke handheld models don't have head gaskets. They have gaskets under the cylinder jug, but they don't have heads. There is no gasket for compression to be lost through. The fact that the original poster is thinking they are losing compression through a head gasket makes me wonder if they have a 2 stroke or 4 stroke engine, because losing compression through a head gasket is possible with a 4 stroke, but not possible with a 2 stroke like what is commonly seen on handheld blowers.

Kinda hard to tell what's wrong with something when we don't even know what that something is.
 
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Old 01-20-10, 08:11 PM
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Strider380,,, If it's only a year old would it not still have a warranty??? Most have 2 to 4 years on them now.. You never did tell anyone what make / model you have.. Is it a name brand or an offshore Chinese build?? Roger
 
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Old 01-21-10, 09:46 AM
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It's a Poulan. I think it has a warranty but noone can find the reciept. I just remeber a two stroke motor that my friend put on his bicycle. The gasket kept blowing out between the jug and lower end. It had no compression and it wouldn't run until you put a new gasket in. Sometimes you could even use rtv.
 
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Old 01-30-10, 05:34 AM
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I've had two or three of these gas blowers. After using them for a while they lose compression. This is caused by they ring in the piston wearing out or getting stuck. The ring should be loose in the piston. Check to see that it is not stuck. When these blowers do not start, this is the cause 90% of the time.
 
  #11  
Old 01-30-10, 05:41 AM
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Originally Posted by dsawyer View Post
I've had two or three of these gas blowers. After using them for a while they lose compression. This is caused by they ring in the piston wearing out or getting stuck. The ring should be loose in the piston. Check to see that it is not stuck. When these blowers do not start, this is the cause 90% of the time.
How long is 'a while'? Let's say in tanks of fuel or hours...
 
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Old 02-03-10, 08:47 AM
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Originally Posted by LawrenceC View Post
How long is 'a while'? Let's say in tanks of fuel or hours...
These blowers are good for 50 hours of running time.
 
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