Husqvarna 372 XP conundrum

[phraggo]

This is my first post but I've read a lot of Husqvarna 372 XP posts.

I have the X-TORQ version of this saw. I bought it new last year and used it to good effect all summer and fall - probably 30 hours of use. This fall I had some trouble getting it started in what appeared to be standard flooding problems. I used the choke off, throttle down, clear the baffles trick to get it running. It ran okay for ~30 minutes. Then she stopped cold. 

Checked the spark, then changed the plug. Cleaned the air filter. No joy.

I called the dealership (now shut down due to COVID). They asked if I'd used Ethanol gas in my mix. I said yes. They said that was likely my problem. Okay. 

Switched to 50:1 Red Armor fuel, cleared the system, tried to start. No joy. Disassembled, blew out and cleaned the carb. No joy. Installed new Husqvarna carb. No joy. Blew out fuel and impulse lines, checked fuel filter. No joy.

Compression is good. Spark is good. Pull, pull, pull. No joy.  :-\

Any ideas?

[TroyC]

Check the flywheel key. I've seen them spin. Everything checked good but would not fire or run.

[Happysawer]

Just might be the right time to sell your Husky and get a Stihl.

[weimedog]

First thing I would do is dump the gas into a glass jar and look for those water works at the bottom of the jar. Could be a spun flywheel. Worth a look, and it could be the ignition even though u see spark. You didn't say if you checked the plug and if was it wet or dry ..

[thecfarm]

Or get another dealer.
Welcome to the forum.
I use the highest grade of gas at my local station. But 4 gallons of gas does not last long, maybe 2-3 weeks.

[sawguy21]

It needs compression, fuel spark and air in the proper amounts and at the proper time to run. Did the plug come out wet or dry? You say compression is good, how did you determine that? Remove the muffler and check the piston skirt for galling/scoring. Is the replacement plug new and properly gapped?

[Southside]

My first thought was fly wheel key too, but how long had the gas sat around?  Both in the saw and in the can before it went into the saw?  Might have a plugged port in the carb.  FWIW I run ethanol gas in my 372's all the time as I am not going to drive 45 minutes to get non-ethanol and pay a premium.  The difference is that we go through 30 gallons of gas a week usually so the issues that ethanol causes don't have time to develop.   

[phraggo]

Really appreciate all the good ideas.

The spark plug is new and properly gapped.

I've double checked gas and it's good (I'm using the same gas that's running my Husky 450 just fine).

The spark plug isn't coming out soaked with gas, but there seems to be fuel getting to the cylinder.

I checked the flywheel key and it's intact with no damage. (That was a good thought I hadn't heard of before.)

I'm getting 90 psi on the compression test (performed with a tester). This seems low - too low to give the carb enough impulse for the fuel pump...?

I tested the ignition coil with a multimeter and it's reading ~15K ohms, which seems too high to me. I've order a replacement and we'll see what that does.

Sawguy21 - I haven't yet removed the muffler to check for scoring. My relatively low compression test suggests I need to pull the piston and check the rings. If my new ignition coil doesn't do the trick, I'm going to try that.

[Happysawer]

I am no expert but a new saw with just 30 hours of use, seems if thinking rings are gone, also if you used the same gas&oil as in your other saws with no problems. There must be something else.
Have you called Husky Tech. Support and tryed getting an answer?

[Real1shepherd]

That's a low enough compression reading on a newer saw to suspect your compression tester....try it on a known working 'well' and starting well saw.

Below 120psi, your saw will start and run marginally or not at all. Weed whackers and smaller cc 2cycles can get by on lower compression numbers, but not usually ported saws(by saying "ported" I mean modern saws versus older reed valve saws).

Kevin

[ladylake]

 
 As mentioned pull the muffler, if that 90# is right its way too low.  Steve

[mike_belben]

My bet is you got a dead piston.

[Real1shepherd]

Could be stuck rings or aluminum transfer from damage. It it's cold start transfers from not letting the saw warm up during its life, those are off to the side of the cylinder and you won't see them by pulling the muffler and carb.

If you are sure your compression tester is reading accurately, I'd pull the jug and look for damage.

Kevin

[weimedog]

90lbs compression isn't good compression, so my first suggestions assumed as you said "good compression". A typical 372 will be in the 150lbs range stock and will not run well if it's below 120lbs if at all. My bet is it won't run at 90. Next is why is the compression so low. Was it straight gassed, did a bearing let got sending debris up thru the transfers and waste the top end. A lot of reasons....my bet is the dead top end was caused by something else...as usual. Time to tear it down to the cases, split the cases and check the bearings.