Husqvarna 51/55 Build

over the summer I got 3 x 55’s and 2 x 51’s and they’ve been sitting in bins under the bench since. Pulled them out this afternoon to take a look at what’s there. After compressions tests on those with cylinders and eyeballing the clean up effort on each, I’m going to take a 55 top end with 165 #’s and match it to a really clean 51, which came with nothing north of the base gasket.

 

I taught my son how to work on saws with this series Husky. They ended up doing very well on resale too. You have any closed port cylinders?

 

Learn me what is closed port?

 

Got through it this afternoon. Sequence above is off, but you get the idea.
Things looking good!

 

And then took it out run.
Pulled over real hard. I put a new Caber ring on. So that may be part of it. I think the pull start is part of the issue too.
Got to light off, but ran like crap.
Discovered the intake gasket had fallen while putting the intake sandwich on
So I fixed that.
Was sure that would make it run great, but it didn’t.
It was better.
I used a new Farmtech carburetor. I’m hoping that’s the issue.
I’ll mess with it after Christmas

 

This is a closed port cylinder (I can't find pics of the 55 one we had)

And this is open port.

 

So the transfers are bridged.
Got it.
The only one I pulled was the 55 with 165#’s and it was open.
Thanks for the pics and lesson.
I’ll check’m out. Do you want a closed port?

 

No. Just wanted to inquire, they are few and far between. Some have said they are better runners, but my son and I swapped topends and didn’t find much difference between the two. If you do get one, advertise it as such and you should get a few more doll hairs for it from those in the know.

 

M2theB Nice thread and nice looking saw all wrapped up! I’m a 55 fan I bought a 55 rancher brand new when I was still in high school and it got abused heavily for a long time. It still runs awesome! It is the open port cylinder.

There wouldn’t happen to be any leftovers from your build is there?

 

I’ll keep you posted on leftovers.
This one is a puzzle.
I have it running better after I put in a new impulse bushing and carb gasket but still won’t idle.
Before putting the piston on I gave the crank and case a heavy dose of 2 cycle oil to lube the seals and bearings. I drained it upside down before assembly but I’m wondering if a big gulp of that on initial start fouled the carb some how.
I’m going to pull the new farmtech carb, clean it and put a rebuild kit in it and see how that goes. I bought 3 of them but they don’t match the Waldbro carbs that came with a couple of the machines.

 

Pretty sure mine runs a walbro couldn’t say what model without looking. As far as the farm tech stuff I haven’t been super impressed with all of it. The last few things I’ve gotten I had to modify slightly to fit.
Give cleaning a try and see what happens. Make sure the jets are clear and don’t have some casting/machine dust in them.

 

Farm Tech carb above, Walbro below I opened up the Farmtech carb and gave it a nice cleaning. I also opened up one of the Walbro carbs that came with the bunch to compare. The only thing that stood out was the jet block on the Walbro just looked like a wider port than the Farmtech. So I gave that good cleaning and put that one in the saw. It definitely performed better. After a little adjustment on the idle screw, it would idle for the a long while. But it still sounds like it’s misfiring at idle. And at Wide Open, it’s not reaching the top. I don’t have a tach, but I can hear it’s just not there. I’m looking for input if you have some. I have one more post coming up before you jump in

 

The dirty saw in the pic is one of the 5 I bought in the lot. After the disappointing result of the carb clean and change out, I started to think about my next steps and realized looking around, the dirty one could actually take fuel as is.
I fueled it and went for it.
5 or so pulls it caught and two more pulls after choke in, it ran. And it sounded good and went to the top and came back to idle. Holy Chit!
When I brought it back to the bench I noticed it was wet around the plug. Right away found it loose. Loose is bad, tight is good?! I tightened it and brought back out to see how much better it would run.
It didn’t. It actually was hard to start and when it did, it ran like the other one. Would not idle.
Why would it run better with a loose plug than a tight one?
I’m thinking crank seals.
I’m not tooled to pressure / vac check. I suppose it’s time to get that way.
Thoughts?

 

Easy. Get yourself a few pieces of inner tube and cut them to block the exhaust port, sandwiched in between the muffler and cylinder, and between the carb and plastic shroud (make sure it covers the impulse hole too). Bust the porcelain out of an old plug and JB an old airline fitting. Then you can use it in the plug hole with a MightyVac to check press/vac.



You won't get any chinese part love from me. I'd much rather clean up an original and kit it.

 

Did you loosen the plug and try it again? I doubt the running different had much to do with the plug tightness. I’m guessing it was more to do with heat after running a bit? I do know that the partition and the two rubber pieces that fit up to the cylinder can be problematic.
Are you able to check compression on both saws?

 

I didn’t try to loosen the plug again yet. I got distracted and got back the first saw today to check for air leaks.
What I found is there is a leak but and it’s cause is the replacement farmtech intake couple between the bulkhead and the cylinder inlet.
Hard to see or get to when installed on the leak test. But seals and temp dams weren’t bubbling but I was loosing air.
I tore the set up apart, plugged the impulse hole and the cylinder intake with my thumb. Low and behold, it held pressure.
I built the test set up again with the original coupling, which looks a feels beefier. It held too!
Going to build the saw back out and see if that does the trick.
That’s the Farmtech in my hand.

 

I'm a snob with these cheap chinese parts. I'd rather pay for oem quality, heck even used oem before chee-na. Especially coils.

 

Gosh darn rubber coupling!!! I’ve always thought it to be a dumb set up just to trust a push on rubber pipe.

 

I agree there.
But it seemed to be a long lived popular saw. You would think if that set up wasn’t doing the job i would read more about it, like the plastic clamp on the 346/350/353/357/359 saws.
Another dumb set up on the Saw is the sandwich bolt from the filter to the bulkhead. I stripped the left one on reassemble!
I started the saw and it acted the same way. Idled ok, kinda high, goosed it up and down a few times and the warmer it got the more it wanted to die at idle. And it finally did.
I’m done with it for tonight.
I’ve ruled out the seal and the base for air leak
I know I have a stripped sandwich bolt, so I’ll deal with that. If getting that tight doesn’t cure it along with some tuning, I think I’m going to look at the carb again.

 

Hmmm I bought mine new in early 2004 and abused the heck out of it. Everything from bad gas to drops and rolling around in my truck bed. Only trouble it ever gave me was two years ago the spark plug bit it mid job!! Since then I’ve done some playing with it, a little grinding and such. I do have to say after the third disassembly I also stripped the threads out of that darn patrtition.
Fuel line and simple stuff is all good? Is that an OE carb?

Forgot to add..... if I get a chance tomorrow I’ll see what carbs on mine and see what the screw turn counts are on her.