Straight gassed

[Daserlon]

A friend of mine gave me a non running husqvarna 272xp. I pulled the starter and it made a funky noise. Then i pulled the spark plug, greyish color. I looked in the plug hole and piston top looked sand blasted, same with inside the muffler. Would that be straight gassed or adjusted too lean? It has spark just no fire. I know, this tread is worthless without pics. I'll try tomorrow.

 

[Kevin White]

Doesn't sound straight gassed to me. You typically wouldn't be able to tell just by looking at the top of the piston or the outside of the muffler. Take the muffler off to where you can see the piston. I'd it looks scratched anywhere in there, depending on where the scratches are could tell you what the problem was/is. I would start there.

 

[jr27236]

Do as Kevin suggested and inspect the piston. Also do a compression test. You could have a saw that failed from many reasons, eg. Straight gassed, poor mix, old gas, leaned out from air leak ect.
Keep posting and youll narrow down your cause and the results from it.

 

[Brewz]

Check inside the air filter to see if its been letting stuff through too.

 

[Chainsaw Jim]

I'm thinking bad fuel causing detonation if the piston crown looks sand blasted.

 

[Daserlon]

Thanks for the info. I'll pull the cylinder to get a good look at things in there. The saw is in pretty rough shape so it may just be a parts saw for my 268 and other 272.

 

[TJ the Chainsaw Mechanic]

 

[Landmark]

Thanks for the info. I'll pull the cylinder to get a good look at things in there.

 

[TJ the Chainsaw Mechanic]

^^^^But not healthy for the faint of heart.

 

[Daserlon]

Finally pulled the cylinder.
Looks sandblasted inside the muffler.
A bunch of silver colored deposits in the exhaust port.The cylinder is scored with silver colored deposits at the top.The piston is scored on the exhaust side with the silver deposits on top also.

 

[jr27236]

How the the bottom end look? Is there oil in case and on all surfaces or is it completely dry? The one picture looks dry and if so I'd say straight gassed. Either way the damage doesn't look too severe, looks to me that cylinder can be cleaned up, put a new piston in and wrist bearing. Check the lower end bearing for fit and lube directly with 2 stroke oil. Do the same when you reinstall the new piston. Oil, oil, oil. It will smoke like sh$%, but will aid the first start up.
The saw was given to you, and if its in ruff shape other then what you shown in pics, just get a Meteor piston for it and don't make it a money pit.

 

[Lee H]

That saw flat out ran lean. Bad fuel, Carb adjustment, Air leak.
Looks like the operator caught it time where there isn't much scoring.
Whats the other side of the piston look like.

 

[Daserlon]

That saw flat out ran lean. Bad fuel, Carb adjustment, Air leak.
Looks like the operator caught it time where there isn't much scoring.
Whats the other side of the piston look like.

The intake side looks good.

 

[Daserlon]

How the the bottom end look? Is there oil in case and on all surfaces or is it completely dry? The one picture looks dry and if so I'd say straight gassed. Either way the damage doesn't look too severe, looks to me that cylinder can be cleaned up, put a new piston in and wrist bearing. Check the lower end bearing for fit and lube directly with 2 stroke oil. Do the same when you reinstall the new piston. Oil, oil, oil. It will smoke like sh$%, but will aid the first start up.
The saw was given to you, and if its in ruff shape other then what you shown in pics, just get a Meteor piston for it and don't make it a money pit.

I only looked at the top end. I'll check the bottom tomorrow. I've got another p/c. The donor saw must have been run over because the cylinder is missing fins. I dont know if it'll cool good enough now.

 

[jr27236]

Just clean up the cylinder you have with Emory paper, if the score didn't go through the plating in the cylinder, you can use muriatic acid to help remove the aluminum transfer. Put it on a qtip. You can use the donor piston, but id re-ring it before you do. If it were me, I would just go with what I advised earlier. I would not use that broken finned cylinder for anything but a paper weight.

 

[jakethesnake]

I only looked at the top end. I'll check the bottom tomorrow. I've got another p/c. The donor saw must have been run over because the cylinder is missing fins. I dont know if it'll cool good enough now.View attachment 43411

If you keep that clean it'll run likely for a long time if the other is salvageable might use it instead Certainly could have that welded up with some doner fins off the old cylinder

 

[Daserlon]

I checked the bottom end and it has a film of oil on it. I didnt notice any excessive play in the bearings but i'm not too familiar with bottom end bearings.

 

[Landmark]

Pressure and vac test will show if theres a leak somwhere. Seals, case gasket etc...

 

[Daserlon]

I dont have the equipment for that. I've never even seen it done. Guess i better get a mityvac. I've got a 2100 and a 288 that probably need tested too.

 

[Mark71gtx]

Putting a saw together without pressure and vacuum testing is madness. It can get expensive quickly to skip that step. The best time to test is when it is going together. You don't want to have to take it apart again just so you can run the tests.