Husqvarna 288XP/G288 Pressure Test Help

[Husse88]

Hi all,

I have tried to pressure test a small air leak in my 288, but failed so far. Long story short, saw is running nicely, but:

• rpm rises when clutch faces down, however no luck with runtime carb clean test
• noticed that fuel was mixed with oil in the oil tank after couple of hours runtime, super weird right? Only possible routes are through the case or oil pump hose?
  • Thought of course aftermarket case gasket was blown, so I have tried a few things to identify possible crank case leak, but no luck so far (filled cylinder with gas->no obvious leakage into oil tank)

So, after all of this I tried to pressure test the saw by blocking intake and exhaust by home-made gaskets, but the pressure test needle only wants to go up to 0,1-0,3 bars, so def is a leak somewhere. Sparyed a lot of soapy water everywhere including gaskets, even oil tank, but no obvious leaks...

I was thinking of buying the OEM pressure test plates for the saw and ultimately split the case and redo the saw if nothing works.

Anyone had similar issues with pressure tests and/or gas in oil tank for some reason?

Pic of the setup, grateful for all help!

 

[bwalker]

The chicom clone saw saga continues.

 

[lone wolf]

The chicom clone saw saga continues.

 

[2StrokeFondler]

Hi all,

I have tried to pressure test a small air leak in my 288, but failed so far. Long story short, saw is running nicely, but:

• rpm rises when clutch faces down, however no luck with runtime carb clean test
• noticed that fuel was mixed with oil in the oil tank after couple of hours runtime, super weird right? Only possible routes are through the case or oil pump hose?
  • Thought of course aftermarket case gasket was blown, so I have tried a few things to identify possible crank case leak, but no luck so far (filled cylinder with gas->no obvious leakage into oil tank)

So, after all of this I tried to pressure test the saw by blocking intake and exhaust by home-made gaskets, but the pressure test needle only wants to go up to 0,1-0,3 bars, so def is a leak somewhere. Sparyed a lot of soapy water everywhere including gaskets, even oil tank, but no obvious leaks...

I was thinking of buying the OEM pressure test plates for the saw and ultimately split the case and redo the saw if nothing works.

Anyone had similar issues with pressure tests and/or gas in oil tank for some reason?

Pic of the setup, grateful for all help!

View attachment 1189438

Sounds like a massive air leak, if the thing won't hold pressure above 0,3 bar. If you can't find it with soapy water, I'd say the clutch side is probably your problem. The oil pump housing has an O ring that has to seal, and the aftermarket ones have been known to be hit or miss. Due to the way it's constructed, the soapy water won't reach the leak, and you don't get any bubbles.
I would put a small amount of motoseal/dirko on top of the O ring, reassemble, let it cure over night and test again. Given the O ring is there and not damaged. If that doesn't work, you can remove the coils and carb, and submerge the whole thing in a bucket of water. You'll find the leak for sure.
Don't get distracted by the "muh, Chinese" crowd.

 

[singinwoodwackr]

Sounds like case gasket failure. Split the case, lap both halves to ensure you have flat surfaces. Reassemble

 

[stihltech]

Dunk in a 5 gallon bucket of water and pressure test. You will find the leak. Find it first, then repair.

 

[KTM 350]

Fuel line off carb ? tested ? fuel tank and oil tank sealed to crank case. Tested all three chambers . Yes, the fuel tank should not matter on this saw. Not all saws have a separate fuel tank.
Lay saw on it's side and" fill" test oil pump side . Put some pressure on the crank (push/pull) .
Flat plates and some rubber (old MC tubes) can make your own sealing plates.
Remove carb and muffler. Seal with plates and rubber. Make sure impulse line/port is sealed.
Seal fuel and oil tank. Tire plugs can work to seal vent holes when lines can not be. . Skinny cheap black ones work.
Retest with soap and water. Watch that oil tank vent/pick-up line holes.
Still can't find. Remove coil and bucket test. Just give it a good clean after, as water will find it's way into everything.
Big leaks are easy. Said the guy not doing it.
As I work in a shop that also has a smoke machine for evap testing. Only problem is it only looks for pressure leaks, not vacuum. Does a good good job on 2 cycle motors though the export port. Smoke starts coming out all the holes most of the time. Quick and dirty way. Only need remove exhaust and I have plates for all of the work (fire department) saws.