New jug and piston in 55R

[jbrody44]

I put a new jug and piston set in my Husq 55R today, it seems like it builds too much compression in the up stroke for some reason. Pulls great with the plug out then with it in, it seems to pull way too hard. I don't think I should try to start it like this. Any thoughts? Thanks - JB

 

[jokers]

Yeah, you`re used to low compression.

I assuming that the engine will turn a full revolution without binding anywhere?

Russ

 

[jbrody44]

Yeah, it turns great. With the plug out it turns very smooth and free. With the plug in it turns but seems to build so much compression toward the top of the stroke, then it releases when the piston reaches the exhaust port. I am stumped. Could the piston be for a shorter stroke 55R?

 

[jbrody44]

Well, I took it all apart again. The top of the piston actually has a small mark on it from it contacting the plug! Seems like my con rod is too long for this jug set, or the jug is too short. Is there some sort of spacer that I am missing that goes under the jug? The set looks identical to the one that I removed from the saw. I ordered it from jackssmallengines.com right from the 55R page. I am at a loss here. Any help is much appreciated. Thanks - JB

 

[Stumper]

Are yiu certain that you have the right plug? Just thought I'd ask before you chase more complicated problems.

 

[cbfarmall]

Compare it to your old piston/jug. Do you have the base gasket? What you found is pretty scary. Be glad you didn't try to start it up. You would hear a hammer that would shake the house.

Chris B.

 

[jbrody44]

I tried the same plug that I had in the saw with the old jug. The new gasket set came with 2 base gaskets, I tried stacking them both and it still seems too tight. Maybe I need to make a thicker gasket? Thanks - JB

 

[HUSKYMAN]

I am not aware of any different pistons or cranks in the 55 or 55R. The only difference is the port timing. Maybe they gave you one from a 350 or something. Call them and recheck the part numbers

 

[jokers]

Hi JB
Sorry for my smart a$$ reply to your initial post. I didn`t realize from reading it that you were actually having any contact issues.

Have you checked the part #s to be sure that you got the right ones? The part #s at the Jack`s site are correct for your application.

Keep us informed.

Russ

 

[jbrody44]

Hey Russ;
I like smart assed remarks, I live for them in fact! No offense taken at all . The part numbers do check out. I received a PM from a member suggesting that I make sure I have 20 thous. of clearnace at the top of the compression stroke. I may need to add a base gasket to do so. I am going to work on it now and will update later on. Thanks all - JB

 

[jbrody44]

She is up and running! I added a second base gasket (2 were sent in the gasket kit) and the plug is not being contacted any longer. Well I am going to go mix up a fresh gallon of 40-1 and check out Madsen's page on carb tuning. - JB

 

[cbfarmall]

That sounds fishy, having to add a base gasket. And it's even worse that the problem was expected and were sent two. Is this common?

Chris B.

 

[HUSKYMAN]

Two gaskets could be a problem after a few years

 

[jokers]

Yeah, something is definitely FISHey.

Some saws have two different thickness gaskets available but I`ve never seen one where you are expected to use both at the same time.

I`m assuming that the sparkplug has the right washer on it. Maybe an indexing shim under the plug would be a viable solution also.

I wonder if the head at the sparkplug hole is thinner than normal?

I love a puzzle, wish I had the saw here.

Russ