Help me out Stihl Bros. MS310

[Dub11]

Yup ^^^^^^ on the transfers

 

[XP_Slinger]

Looks AM to me. Can't see any markings on the recoil side.

 

[RIDE-RED 350r]

Yes sir it is. Here's a pic of some of the gold mine.
View attachment 70205

Hey!! In the very top right corner of that pic, you can see the 242xp that is no longer there!!

 

[XP_Slinger]

Hey!! In the very top right corner of that pic, you can see the 242xp that is no longer there!!

 

[fearofpavement]

I build a lot of the 1127 series saws and if this thing has been redone and doesn't work right, it's probably one of 3 different things.
1, these engines are very prone to air leaks during assembly. Pressure test it and see if it passes.
2. It's probably not an MS310 cylinder but a 49mm cylinder from the MS390. If so and the muffler is restricted it will run bad. It needs a muffler mod.
3. If the fuel line is aftermarket, it's probably pinched off where it makes the bend to go into the carb. I've found only about 1/3 of aftermarket fuel lines will work. The aftermarket impulse lines are fine.

If the limiters haven't been trimmed, that will have to be done.

 

[XP_Slinger]

I build a lot of the 1127 series saws and if this thing has been redone and doesn't work right, it's probably one of 3 different things.
1, these engines are very prone to air leaks during assembly. Pressure test it and see if it passes.
2. It's probably not an MS310 cylinder but a 49mm cylinder from the MS390. If so and the muffler is restricted it will run bad. It needs a muffler mod.
3. If the fuel line is aftermarket, it's probably pinched off where it makes the bend to go into the carb. I've found only about 1/3 of aftermarket fuel lines will work. The aftermarket impulse lines are fine.

If the limiters haven't been trimmed, that will have to be done.

Thanks man. I'm going to wrench on it some more tomorrow morning. Before I tear it down to replace cranks seals I'll pressure check it and go from there. I still think there's something goin on with the fuel system. It's not running like other saws I've had with bad crank seals. Guess I'll find out

 

[Dub11]

I build a lot of the 1127 series saws and if this thing has been redone and doesn't work right, it's probably one of 3 different things.
1, these engines are very prone to air leaks during assembly. Pressure test it and see if it passes.
2. It's probably not an MS310 cylinder but a 49mm cylinder from the MS390. If so and the muffler is restricted it will run bad. It needs a muffler mod.
3. If the fuel line is aftermarket, it's probably pinched off where it makes the bend to go into the carb. I've found only about 1/3 of aftermarket fuel lines will work. The aftermarket impulse lines are fine.

If the limiters haven't been trimmed, that will have to be done.

Your right on the 49 mm part it has a decomp the others don't.

 

[Adamski]

So bottom line are these 390's (if it's all OEM) worth keeping???? This is the conundrum with mine, haven't made a cut with it yet, but managed to get it up and running last night.

 

[Dub11]

So bottom line are these 390's (if it's all OEM) worth keeping???? This is the conundrum with mine, haven't made a cut with it yet, but managed to get it up and running last night.

There good saws. Just some cool kids aren't fans of them. I have a 290 and it always starts up and cuts. So I can imagine adding 7cc will just make it better.

 

[Adamski]

What I will say is that this 390 with a muffler mod, advanced timing and matching the piston window to the cylinder transfers has made what looks to be a loud, loud screamer. It is also very very snappy with it's throttle response.. Just need to actually tune it in the cut at the weekend.

 

[Deets066]

I used to have a modded 390 that was very impressive. Wish I still had it today

 

[XP_Slinger]

I used to have a modded 390 that was very impressive. Wish I still had it today

We all have those don't we Deetsy

 

[XP_Slinger]

Your right on the 49 mm part it has a decomp the others don't.

Just got up having muh morning coffee, I'll be heading to the bench in a little while. Good to know I already have a 390 top end. My friend has a 391 and I like the power it has.

 

[Adamski]

We all have those don't we Deetsy

Yep had a 044 that I recently parted with... A 266 and a 154/254xp last year... A Pioneer 1560 (8 years ago)

All the funnest saws I have used and owned

 

[XP_Slinger]

Referencing the carb spit back; anyone know the metering arm setting for this HD21 off the top of their head?

 

[XP_Slinger]

That sealant looks fresh

Forgot to respond to this. The PO had a dealer put a new top end it, saw still ran the same afterward. PO said he only started it 3 times to try to tune it after the P&C change. They ended up talking him into buying a different saw. They said the saw wasn't worth what it was gonna cost to get it running right.

 

[Dub11]

Forgot to respond to this. The PO had a dealer put a new top end it, saw still ran the same afterward. PO said he only started it 3 times to try to tune it after the P&C change. They ended up talking him into buying a different saw. They said the saw wasn't worth what it was gonna cost to get it running right.

Thats a pretty lame way of selling a saw if ya ask me. I would avoid that dealer

 

[Adamski]

Referencing the carb spit back; anyone know the metering arm setting for this HD21 off the top of their head?

Nope but I took a guess of the standard flat to the top of the carb body when I set it last night. Started straight away and sounded good (havn't tested it in the wood though) and reved, ticked over an was all OK so far.

 

[XP_Slinger]

Thats a pretty lame way of selling a saw if ya ask me. I would avoid that dealer

Damn right it is. I told him the same thing. I told him to bring his saws to me if they need work so he can at least get an honest assessment of what needs to be done. Also told him that if I get this 310 running I would give it back to him for the cost of parts required to fix it but he insisted I keep it.

 

[XP_Slinger]

Nope but I took a guess of the standard flat to the top of the carb body when I set it last night. Started straight away and sounded good (havn't tested it in the wood though) and reved, ticked over an was all OK so far.

Good to know. Mine was well above the carb body on initial tear down. I set it even and it helped. The pump diaphragm is rigid as all hell, no sag to it at all. Maybe it's ok but I've never seen one with out at least a little sag.