Husqvarna 350 Rebuild

[ChillyB]

I have 3 350's set aside for rebuilds. 2 of them are getting crank bearings and seals. I went with OEM seals and SKF bearings. I will keep this endplay problem in mind...... hopefully I'll remember to remember it! LOL

I can’t say that I came up with a satisfactory way to get the end thrust I wanted. Because the seals are integral to the bearings you can’t get a good feel for end clearance, except when it’s wildly loose. Maybe looping a piece of thin wire between the inner race and crank thrust surface before loading the crank assembly would work, then hope you can pull the wire out once seated? The thrust surface isn’t large enough to reliably hold feeler gauge, but maybe someone with extra helping hands could manage it.

 

[ChillyB]

Passed. Two layers of blue masking tape on exh port, gasket and muffler over that. Slobbery thumb on intake boot and impulse port. Autozone loaner HVAC test pump.

 

[ChillyB]

One lingering question: will my new ring break in? I didn’t do anything to the cylinder bore surface. Still showed significant hatching. I guess if my compression ends up low I’ll know what to do next.

 

[grizz55chev]

One lingering question: will my new ring break in? I didn’t do anything to the cylinder bore surface. Still showed significant hatching. I guess if my compression ends up low I’ll know what to do next.

Run a few tanks of fuel through it before tearing it back down, should see a considerable improvement in comp. Be patient and the power will improve, and some adjustments in fuel mixture will be needed as it breaks in. No need to baby it either, run it like you stole it!

 

[ChillyB]

Yeah, I’ll let the saw decide what to do about it.

I watched a few videos on top end rebuilds. Don’t recall anyone deglazing the bores. If it was cast iron I would have done it, but figured the plating wasn’t made to be rehatched.

What I did see on my piston was some carbon staining below the ring. Ring was also shined across its entire height. Are chainsaw rings tapered, where full polish would indicate a used up ring? I may have used marine oil sometimes since I used to have a small boat. Back then I didn’t figure there was a difference. Maybe that didn’t help my ring.

 

[grizz55chev]

Yeah, I’ll let the saw decide what to do about it.

I watched a few videos on top end rebuilds. Don’t recall anyone deglazing the bores. If it was cast iron I would have done it, but figured the plating wasn’t made to be rehatched.

What I did see on my piston was some carbon staining below the ring. Ring was also shined across its entire height. Are chainsaw rings tapered, where full polish would indicate a used up ring? I may have used marine oil sometimes since I used to have a small boat. Back then I didn’t figure there was a difference. Maybe that didn’t help my ring.

Please don't get started on oil discussions, !

 

[9050LX]

Can’t forget what you don’t take out. Same way that I don’t mix up screws. Once I pull a part or loosen a mount the screw goes back in the hole. I don’t toss the screws in a coffee can and hope I remember where they went.

Only experts throw all there screws in coffee cans,lol point is,anyone who rebuilds these will forget that ground strap eventually.most of us prefer zip lock bags for parts.

 

[grizz55chev]

Only experts throw all there screws in coffee cans,lol point is,anyone who rebuilds these will forget that ground strap eventually.most of us prefer zip lock bags for parts.

I've pieced many of these 350s together from parts, they are drop dead simple.

 

[9050LX]

They certainly are.

 

[ChillyB]

All together. The Chinaman won out with the muffler. For now. I’ll still mod the original when I come upon some small diameter tube.

One last assembly question: is ther a torque spec on the flywheel nut?

 

[skeet88]

Saw looks great. Can’t wait to hear how it performs.

 

[ChillyB]

Well, I’m not quite sure how it performs. Fires up easy, idles nice, high speed seems rich but screw is only at 1.25 turns. I’m not an expert at tuning but it sounds rich. Maybe my tuning ear isn’t trained yet. I’ll go fatter and see what happens. Can’t hardly think I should turn it in any more. Using 40:1 canned gas.

 

[Bob Hedgecutter]

Well, I’m not quite sure how it performs. Fires up easy, idles nice, high speed seems rich but screw is only at 1.25 turns. I’m not an expert at tuning but it sounds rich. Maybe my tuning ear isn’t trained yet. I’ll go fatter and see what happens. Can’t hardly think I should turn it in any more. Using 40:1 canned gas.

I would run it a wee bit rich for the first few hours of use and fine tune it when it all gets to know itself internally.

 

[ChillyB]

The issue is it seems rich to the point of not cutting well. If it wasn’t 4-stroking I’d open the high speed screw. But it IS 4-stroking and seemingly low on power in a cut.

Add to that my rookie paranoia that I’ll ruin my saw.

 

[ChillyB]

I’m going out to Autozone to rent compression tester to get a baseline so I can track break-in.

 

[Bob Hedgecutter]

The issue is it seems rich to the point of not cutting well. If it wasn’t 4-stroking I’d open the high speed screw. But it IS 4-stroking and seemingly low on power in a cut.

Add to that my rookie paranoia that I’ll ruin my saw.

Too rich wont ruin it quick- too lean will.
Peak revs at WOT, turn the screw out small increments until you notice 4-stroking take it out a wee tad more.
Compression readings will not alter your tuning.

 

[Woodslasher]

If it is running rich, why not lean it out? 1 turn out is a good baseline for saws so it being too rich at 1.25 isn’t really odd. Another thing you could check is your metering lever/pop off pressure isn’t set too high. Lastly, check your pop off pressure. If it’s too low the saw will start dumping fuel in too early, you’ll want it to be around 15lbs or so. To test your pop off pressure, just hook a pressure gauge to where the fuel line goes on the carb and pump it until it “pops” and starts losing pressure.

 

[ChillyB]

Too rich wont ruin it quick- too lean will.
Peak revs at WOT, turn the screw out small increments until you notice 4-stroking take it out a wee tad more.
Compression readings will not alter your tuning.

I just set it as you recommended. It was indeed rich. Now it’s at only one turn out. I guess I expected to need more turns. I wince at being at WOT unloaded even for a few seconds.

 

[ChillyB]

180 psi.

 

[BrettS]

Don't push the bearings all the way into the seals, what I ended up doing on my 350 was to fit the bearings against the crank webs and fitted the seals so they butted up against the outside face of the seal pockets, I then put the assembled crank on top of the seals to see where the seals would fit the bearings and put a mark on the bearing and pushed the seals up to that mark then fitted the crank assembly and everything lined up nicely.