MS362 head scratcher

[leedeerman]

One for the saw experts here

 

I got a seized MS362, I've done a full rebuild on it, piston, barrel, crank bearings, all gaskets and crank seals (all genuine Stihl).

 

Once rebuilt I can not get it to pick up RPMs at all, it'll tick over not too bad but when you give it some throttle it bogs right down and then stalls when you release...

 

Any ideas any one?

 

I did swap the carb for a known working one to rule it out, it made no difference, I was wondering if the coil could be faulty?

 

I've done a few rebuilds which normally go well, this one has me stumped a bit.

[Stubby]

It would seem every one else is scratching their heads as well judging by the views you have ! . Spud will be along some time . Assuming you have tried another known working coil it sounds like a " flow , or lack of flow " thing . You are asking it to accept more air and fuel and it is not accepting it for whatever reason . Is something blocked somewhere . Carb boot , air intake , fuel line , fuel filter , tank vent etc etc .........

[leedeerman]

It would seem every one else is scratching their heads as well judging by the views you have ! . Spud will be along some time . Assuming you have tried another known working coil it sounds like a " flow , or lack of flow " thing . You are asking it to accept more air and fuel and it is not accepting it for whatever reason . Is something blocked somewhere . Carb boot , air intake , fuel line , fuel filter , tank vent etc etc .........

 

Good call, I haven't checked fuel line and pickup

[spudulike]

Impulse line, split manifold, split fuel line!

[njm]

Check the fuel line elbow is ok , also had a few Stihl's with a vertical split up the fuel line ..

[jpmlfc]

i would say say check all above but also check the exhaust make sure it isn't blocked and also check the flywheel woodriff

[Stubby]

Thats a point . When you rebuilt it you may have inadvertently miss aligned the fly wheel sheering the woodruff key making the timing shift .

[spudulike]

Check the linkages on the carb are set up right. I had one that a customer had taken apart and it was doing pretty much what yours is.

 

Make sure the choke comes off when the choke lever is raised and make sure the throttle valve opens when the throttle is opened and make sure the strato valve opens low to mid revs. It is easy to get the linkage wrong - worth taking photos when doing them as it jogs the memory - the 550/560XP choke lever is a classic case of this!

[leedeerman]

Thanks for your all your tips on this one, but no joy today, here's where I am now before I run over it in the telehandler!

 

Today I changed the pick up, blew the fuel hose and impulse pipe through and both pressure tested them both, I also made sure the impulse to crankcase connection was clear and also removed the manifold and checked, I've checked the timing on the fly wheel and the key way which all seem fine, I also changed the coil for a known good one and once again swapped the carb for the same in case I missed something, again symptoms exactly the same, I really am at a loss, I'm normally spot on with saws.

 

What I'm thinking now is the crank is a little tight when turning by hand

but not overly I think, would this cause the symptoms? I did intially strip and reset the bearings in case the were wrong, or the other things is I got a massive air leak from some where but all seals and gaskets are new a look good? Or last thing that the big end bearing is worn, but to be honest I could hardly feel any play in it.

 

One last thing worth a mention I don't know it's full history as far as I can n see all the parts look to be the right ones.

 

Looks like I need to pressure test the bugger!

 

Any advice muchly appreciated.

[njm]

Thanks for your all your tips on this one, but no joy today, here's where I am now before I run over it in the telehandler!

 

Today I changed the pick up, blew the fuel hose and impulse pipe through and both pressure tested them both, I also made sure the impulse to crankcase connection was clear and also removed the manifold and checked, I've checked the timing on the fly wheel and the key way which all seem fine, I also changed the coil for a known good one and once again swapped the carb for the same in case I missed something, again symptoms exactly the same, I really am at a loss, I'm normally spot on with saws.

 

What I'm thinking now is the crank is a little tight when turning by hand

but not overly I think, would this cause the symptoms? I did intially strip and reset the bearings in case the were wrong, or the other things is I got a massive air leak from some where but all seals and gaskets are new a look good? Or last thing that the big end bearing is worn, but to be honest I could hardly feel any play in it.

 

One last thing worth a mention I don't know it's full history as far as I can n see all the parts look to be the right ones.

 

Looks like I need to pressure test the bugger!

 

Any advice muchly appreciated.

 

Bent crank is a poss , if the saw stopped dead at max rpm it could twist the crank , this would cause air leak at seals