254xpg help please

[Yoopermike]

Just did. Sprayed corner of gasket and revd up. So definitely have a leak either on the base gasket or seal on flywheel side


Thanks a lot fellas.

Yep, the seal on on the flywheel side is blown on my 254. currently waiting for them to arrive. Glad you found the air leak.

There are three tapped holes near the mounting holes on the seal holder. You can use the seal holder mounting screws, thread them in those other holes and they will push the seal out part way. They will NOT push it out all the way so don't force them after the seal starts moving. Treat them like you would head bolts and tighten each one a little more in series so that the seal is pressed out evenly. Usually once they are started they will pop the rest of the way out with a pick or similar tool.

Yep. I got mine out last night doing that trick
I hope I ordered the right seals though. the one that popped out of my 254 didn't have a metal outer sleeve the ones that said they were for a 254 have the metal sleeve on them.

 

[Welder56]

There are three tapped holes near the mounting holes on the seal holder. You can use the seal holder mounting screws, thread them in those other holes and they will push the seal out part way. They will NOT push it out all the way so don't force them after the seal starts moving. Treat them like you would head bolts and tighten each one a little more in series so that the seal is pressed out evenly. Usually once they are started they will pop the rest of the way out with a pick or similar tool.

I'll remember that for sure

 

[Agrarian]

Lol I've done both tests without issue. I had the vacuum up quite abit and left it. Came back 20 mins later and it didn't move a hair.

Can I ask - what value is "up quite a bit"? I am assuming you are using the MityVac which measures in in-hg.

 

[Agrarian]

I hope I ordered the right seals though. the one that popped out of my 254 didn't have a metal outer sleeve the ones that said they were for a 254 have the metal sleeve on them.

The current parts do have an outer metal sleeve now - must be a design improvement.

 

[Welder56]

I went to 9hg I guess. Held no problem.

Will try again tonight. I have it all setup. Should still be hooked up since I left vacuum on it. So ill see if it dropped after a 4 hour time frame LOL

Im determined to fix it just don't know the problem yet. Hope to find the culprit damnit

 

[Welder56]

10inhg for 2 minutes. Didn't move a hair

 

[Welder56]

That black plastic piece behind the flywheel had a loose bolt..... put the lock tight to the seal holder, generator and plastic piece. Hope that does the trick

 

[zeke573]

You are running without a bar and chain? Without a bar and chain,the saw may be slower to drop in rpm after revving. There is no chain weight/drag to pull the rpms down as fast as normal. A bad clutch spring can cause similar issues because the shoes stay engaged longer than they should and it gets magnified with no bar/chain. Also, too lean on the L screw will cause this to an extent. You need to get a bar and chain on there to really figure out what is going on.

Pressure test with the intake block on. The gasket from block to cylinder is a prime area for a leak on this saw. New gasket or not, you still need to verify that area is ok. Other than that,sounds like you are airtight from the tests you have already done. Bad carb would be possible as well.

 

[backhoelover]

Did u try carb cleaner around carb while running


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[drf255]

You are running without a bar and chain? Without a bar and chain,the saw may be slower to drop in rpm after revving. There is no chain weight/drag to pull the rpms down as fast as normal. A bad clutch spring can cause similar issues because the shoes stay engaged longer than they should and it gets magnified with no bar/chain. Also, too lean on the L screw will cause this to an extent. You need to get a bar and chain on there to really figure out what is going on.

Pressure test with the intake block on. The gasket from block to cylinder is a prime area for a leak on this saw. New gasket or not, you still need to verify that area is ok. Other than that,sounds like you are airtight from the tests you have already done. Bad carb would be possible as well.

I think this is your answer.

There's nothing to hold back the inertia of the cranks rotation. It seems like it's normal to me for a saw with no chain. Mine act the same.

Mount a bar and chain. Retest. Seems normal to me.

 

[drf255]

A throttle plate that's too far open in the carb could cause it as well. As in if it needs to open far to idle right because of a bad idle circuit or adjustment.

 

[pioneerguy600]

I will lend you a bar and chain for it so it has some weight and drag applied to the clutch. We need to meet to swap parts and have a coffee.

 

[Welder56]

Sounds good Jerry. I got a bar and chain coming for it. I can swing by value sales and get one today.

Will install bar and chain and try again. Glad I went though it again because of the loose bolt. There was bubbles behind the bolt as well.

 

[pioneerguy600]

My bet, it`s the carb causing the issue. Do you have another working carb for it?

 

[Welder56]

No that was my only good one....

I'll call mcfarlands and see how much a new one is after putting a bar and chain on and seeing if it runs fine

 

[Agrarian]

No that was my only good one.... I'll call mcfarlands and see how much a new one is.

If you go the route of replacing the carb, you can use an HDA-35 (earliest with capillary check valve), HDA-107 or HDA-101. The Walbro site still shows the 35 and 107 as active parts that can be ordered, the 101 substitute is the 35.

 

[Welder56]

I'm gonna try my hardest to use the hda35b that I have on it now.

Priced out a new one and its worth me screwing with it LOL

 

[drf255]

Is the throttle plate straight and closing correctly?

 

[BigDee]

I just checked to be sure - you also need to loctite the three screws that hold the flywheel seal holder in place because they also are through bored and tapped.

I have never done this but I sure will in the future. Thanks. Don