372 sputters when tipped, passes spray test

[EFSM]

I swapped the carb to a 385 carb off my smashed XS 2175 this am and I haven’t put a bar on and put it in wood yet but the tune is stable regardless of position, side to side anyway. Nose up or down changes a little bit I think that’s normal. It doesn’t stall. I think those RWJs just kinda stink.

Interesting. From my experience, those carburetors have held up very well. I’ve worked on many a 372 and Ican’t recall even rebuilding one. Then again, I’m not working on shelf queens that live in CA.

 

[davidwyby]

Interesting. From my experience, those carburetors have held up very well. I’ve worked on many a 372 and Ican’t recall even rebuilding one. Then again, I’m not working on shelf queens that live in CA.

Xp or xt?

 

[EFSM]

Either. I’ve worked on way more xt’s though.

 

[Czed]

Seems healthy

Saw is almost new.

I blew it off first (desert wood is filthy dusty)

Not sure if it was sucking air there or I didn’t get it clean enough or…

View attachment 470446

I put a light film of motoseal on all those contact points
Never had a leak.

 

[Junk Meister]

Something else I’ve learned along the way. If your carb screws are normally at one and one, turn the H out 2 turns. Hold the saw wide open and if it hits the screw setting rpm for a split second and then takes off and screams, it’s a flexible leak. 90% of the time it needs new seals. That is the only way that I’ve ever been able to diagnose a seal leak for certain

You aren't walking on water - yer hydroplaning with this troubleshooting analysis. If'ns I keep reading "STUFF" like this I will either get smarter or brainwashed. Simply put this is above my pay grade ..... When you say "Flexible Leak" -- I would hope you will explain better so I don't get my foot where it doesn't belong .

 

[huskihl]

You aren't walking on water - yer hydroplaning with this troubleshooting analysis. If'ns I keep reading "STUFF" like this I will either get smarter or brainwashed. Simply put this is above my pay grade ..... When you say "Flexible Leak" -- I would hope you will explain better so I don't get my foot where it doesn't belong .

Flexible, meaning something that can change size depending on throttle position. There’s vacuum inside the crank case and intake boot when you’re under acceleration. The boot and seals are both rubber. If you rev a saw up to an overly rich H jet setting to intentionally hold RPMs down, a bad seal or tear in the boot will suck in and allow excess air into the crank case to mix with that extra fuel and the RPMs will scream

 

[davidwyby]

Flexible, intermittent annoying confusing obnoxious

 

[Junk Meister]

Flexible, meaning something that can change size depending on throttle position. There’s vacuum inside the crank case and intake boot when you’re under acceleration. The boot and seals are both rubber. If you rev a saw up to an overly rich H jet setting to intentionally hold RPMs down, a bad seal or tear in the boot will suck in and allow excess air into the crank case to mix with that extra fuel and the RPMs will scream

THANK YOU
I wasn't even close to your explanation.

 

[Junk Meister]

Flexible, intermittent annoying confusing obnoxious

Sounds like you're talking 'bout bill collectors or politicians..

 

[Duce]

372's oe or xt are easy to tear down and do complete rebuild. Clean every part, check carb screen, check bearings, base gasket (had one that blew pto side out), tank vent, fuel lines and impulse line, muffler screen, new o-ring (never seen a saw without one, pick around crank, bet you find one), replace seals and base gasket (if you want one), vacuum check, new fuel filter. Make it right once and forget it!

 

[jacktheripper]

Something else I’ve learned along the way. If your carb screws are normally at one and one, turn the H out 2 turns. Hold the saw wide open and if it hits the screw setting rpm for a split second and then takes off and screams, it’s a flexible leak. 90% of the time it needs new seals. That is the only way that I’ve ever been able to diagnose a seal leak for certain

Excellent advice

 

[jacktheripper]

It can be the carb nozzle check valve. I’ve had saws that ran fine in one orientation, but with an iffy sealing check valve, gravity can influence it to not seal correctly. Also, for some strange reason if you don’t have your metering lever or spring set right, I’ve had carbs act oddly when tilted.

 

[jacob j.]

Have you checked the intake boot for cracking?

 

[MG porting]

Seems healthy

Saw is almost new.

I blew it off first (desert wood is filthy dusty)

Not sure if it was sucking air there or I didn’t get it clean enough or…

View attachment 470446

I have found on the aluminum carb base tend to need some shaving around the outer lip that over hangs the portion of the intake boot that seals up against the carb.