346 XP NE seize

[Sidecarflip]

DeComp valves are always suspect and I always use 3Bond. 3Bond is always available at any Kubota dealer, Kubota loves the stuff btw. You can get it in tubes and small jars with a brush, much like Never-Seize.

 

[cscltd]

Isn’t mark on intake a result of phase separation of fuel?

 

[husq2100]

The generic Husqvarna service manual only gives details on pressure testing. Pump up to 0.8 bar & it should not drop below 0.6 bar in 30 seconds to pass.
Does it have decompression valve? If so try pulling on it to help it seal while testing

I tried both pressure and vacuum, it won’t hold either. Pressure + soapy water is the easy way for me (unless it’s so obvious you can hear it lol) That’s how I found the cylinder gasket leaking. Very small bubbles on the flywheel side. I snugged the cylinder screws up , it reduced it some, but didn’t seal it.

I spray around the spark plug fitting, exhaust and intake points, cylinder and decomp.

I’ll double check the decomp tomorrow. I need to get the cylinder gasket sealing properly first.

 

[sean donato]

Don't forget about crank seals....

 

[husq2100]

Don't forget about crank seals....

Definitely not, going through process of elimination before needing to pull the flywheel, clutch and removing oil pump…

 

[sean donato]

Definitely not, going through process of elimination before needing to pull the flywheel, clutch and removing oil pump…

just yank them off. Too much of a pain to do a proper pressure/vac test with the saw fully assembled or even partially disassembled.

 

[lone wolf]

It does not hold at 12 inHg, that’s just the rate of drop. It drops out to zero.

Well get some automotive gasket material and try again.

 

[lone wolf]

just yank them off. Too much of a pain to do a proper pressure/vac test with the same fully assembled or even partially disassembled.

Yup, rip it all the way down and replace all the rubber parts and gaskets and pressure and vac test. Cutting corners leads to wasted money and time!

 

[huskihl]

From 15 down to 12 in a minute isn’t enough of a leak to cause issues.

It was tuned lean, stiff diaphragms in the carb, plugged carb screen, kinked fuel line, bad fuel filter,…some along the lines of that causing a lack of fuel

 

[rupedoggy]

Listen to Huskihl

 

[J D]

I tried both pressure and vacuum, it won’t hold either. Pressure + soapy water is the easy way for me (unless it’s so obvious you can hear it lol) That’s how I found the cylinder gasket leaking. Very small bubbles on the flywheel side. I snugged the cylinder screws up , it reduced it some, but didn’t seal it.

I spray around the spark plug fitting, exhaust and intake points, cylinder and decomp.

I’ll double check the decomp tomorrow. I need to get the cylinder gasket sealing properly first.

Given that you know its leaking at the base gasket, & the leak is minor, & it's an easy fix... if it were mine I'd measure squish, make a new gasket or delete the gasket completely to bring squish down to 0.020", reassemble with threebond or similar, vac/pressure test to ensure leak is gone.
It's a good idea to rotate the crank while testing, guage should flucuate but not loose pressure. This confirms you are testing the whole system (not just a blocked impulse port) & more thoroughly tests the seals

 

[bwalker]

Given that you know its leaking at the base gasket, & the leak is minor, & it's an easy fix... if it were mine I'd measure squish, make a new gasket or delete the gasket completely to bring squish down to 0.020", reassemble with threebond or similar, vac/pressure test to ensure leak is gone.
It's a good idea to rotate the crank while testing, guage should flucuate but not loose pressure. This confirms you are testing the whole system (not just a blocked impulse port) & more thoroughly tests the seals

I highly doubt the problem originated with the base gasket. Unmolested they rarely develop leaks.

 

[J D]

I highly doubt the problem originated with the base gasket.

Agreed.
My advice was aimed at addressing his current situation.
Once that is done he can move on to carburetor, tuning etc

 

[bwalker]

Agreed.
My advice was aimed at addressing his current situation.
Once that is done he can move on to carburetor, tuning etc

As I said previously I would replace all the rubber parts, then pressure/vac test.

 

[husq2100]

Listen to Huskihl

There’s an old name from the past . Hope you’re well mate

Yep I think he’s on to it…

Re did a new temp cylinder gasket, and it now takes over 5 minutes to drop from 10 psi to 9 psi under pressure, and the decomp is blowing tiny little bubbles. I’ll let it sit until it drops out or holds. Then try a vacuum test

Since @huskihl mentioned the carb, I seem to remember a possible primer bulb disintegrating in the past…

I’m of the ain’t broke don’t fix it on things that normally give good service life. Crank seals are one of those. I’ll definitely grab a carby kit with the piston and possibly the intake bits while I’m at it.

Rebuilding carbies is my least favourite, so bloody tiny lol.

Genuine piston & ring kits is US$100 here

 

[husq2100]

Pressure at 30 mins was still 7psi, at 1.5hrs still above 5 psi.

Vacuum, it took over 5 minutes to drop from 15.5 to 15 inHg…. I’d say she’s pretty tight

 

[Jasonrkba]

Maybe I just like spending money but when I get one like that I replace everything. Piston, cylinder, Seals, bearings, gaskets, lines, filter, carb kit, tank vent, intake boots, grommets. like Bwalker said, everything rubber. Eliminate the decomp. Half the time I buy a new air filter and rubber AV's. I understand shops don't always do that because its other folks money but its piece of mind. Maybe that saw had a dull chain?