Husqvarna 142 basic carb settings

[MattG]

Hi Husky peeps,

I'm more used to mending stihls, but a friend of a friend wants me to fix up a Husq 142. I received the usual problem report:

"It used to start, now it doesn't, can you help?"

So compression test, only 120 psi, a bit lame, but I'm guessing it should start right? It does have a good spark. But the carb was horrible, full of all sorts of cack. So I've stripped and cleaned the carb, found some MS200T new carb spares to use for new diaphragm/gaskets/needle etc. and I'm gonna throw back together and give it fresh fuel and see what happens.

So what baseline setting should I apply to the H and L screws? Can anyone just tell me to starting point (e.g. H screw x turns out, L screw whatever turns out etc. etc.)

thanks in advance!
Matt

 

[XP_Slinger]

I always start at 1.5 turns out on both H & L jets. It’s usually a little rich which is where I like to start.

 

[MattG]

I always start at 1.5 turns out on both H & L jets. It’s usually a little rich which is where I like to start.

Thanks buddy, just like I'd probably start off with on a stihl

Do you think that it should *just about* run with 120psi?

 

[ranchdadmike]

Book says 2H, 1.5L. Some kind soul put this spreadsheet together and I’ve referred to it numerous times. I’m like XP_Slinger, usually 1.5 on both H and L to start, but the spreadsheet is nice to have:

 

[MattG]

With all else sorted out, do you think it's likely to fire with only 120psi?

I have worked on an ms231 with only 130psi, and that seemed to run ok....

 

[XP_Slinger]

With all else sorted out, do you think it's likely to fire with only 120psi?

I have worked on an ms231 with only 130psi, and that seemed to run ok....

I would bet that it will run. How well it runs would be the question. I’m not familiar with your particular model but I would expect a healthy one to pump up to at least 140psi. Give her a rip and see how it does.

I rebuilt a 371 for a friend that was down to 125psi, it started a little hard but ran “ok” once it was going. Normal compression for that particular model is 150psi.

 

[MattG]

Well I discovered why the carb was so bad. It had been last run without the filter in place. The filter was just sat in the bottom of the tank, disconnected from the pipe!

Unfortunately even after a meticulous clean (carb blown with cleaner and soaked in gas overnight), a bunch of new carb parts, it would not grace me with a single cough yesterday. I tried and I tried. Damn sure fuel was getting in to engine (damp plug end) and healthy spark. Even wondered if I'd flooded it, and retried after pulling over with plug out and WOT. Not even a single pop.

So I'm now thinking it's the bad compression responsible or it's because so much crap has been sucked in that an inner carb passage is still blocked.

 

[Wonkydonkey]

Matt, it may sound strange but have you tried a known working plug, or try the plug in another saw.
It should at least pop. The 026 I got, I just tipped a bit of gas in the carb throat, 4pulls and she popped, I tipped abit more in and a fast\hot start , that was enough to make it run for a few sec,s

Other than that
Have you seen this thread
http://opeforum.com/threads/husqvarna-450-wont-start.12489/

Turned out to be the coil, even thou it sparked while not under compression

I hope this helps
Cheers

 

[MattG]

Thanks Sean,

The plug is brand new - or at least it looks it. It may close the gap on it a tad......for a stronger spark....but TBH the spark was pretty bright enough to see it garage yesterday, even with some daylight coming in.

Just swapping the plug to a good saw is still a good idea, to eliminate it that variable mind you.

I'm curious as to value that the compression must exceed for an engine to fire.....I'm guessing it can be less than 100psi.....i.e. so that decompression valves don't prevent engines from completely working. Does anyone know?

 

[MattG]

I appreciate a consensus of opinions

Do people agree that with 100-120psi comp there's still enough compression to get a pop from an otherwise decent engine?

In other words, should I rule out compression issue, and focus on ignition and carburation?

 

[XP_Slinger]

Did you ever pull the muffler to see how the piston looks? Is the needle set to the proper height? Were you getting spit back through the carb when you were trying to start it?

 

[XP_Slinger]

Book says 2H, 1.5L. Some kind soul put this spreadsheet together and I’ve referred to it numerous times. I’m like XP_Slinger, usually 1.5 on both H and L to start, but the spreadsheet is nice to have:

Mike, thanks for posting these tables. Awesome info to have.

 

[MattG]

Did you ever pull the muffler to see how the piston looks? Is the needle set to the proper height? Were you getting spit back through the carb when you were trying to start it?

Hey dude!

I've not done much on the saw yet really except cleaned out the fuel system, and changed over the carb needle+diaphragms (along with a thorough clean), checked the spark (good), checked the comp (bad - 120).

I'm not great with huskies (this is the first I've ever looked at).

I'm gonna have to gauge the owners enthusiasm now, I think, as I've put 15 quid of parts on it and a couple hours of work. I think he may need to show that he'll pay up if I keep working from on - now I've discovered that it aint gonna be a "quick fix".

Will post back on this thread if I make more progress or need more help

 

[XP_Slinger]

Hey dude!

I've not done much on the saw yet really except cleaned out the fuel system, and changed over the carb needle+diaphragms (along with a thorough clean), checked the spark (good), checked the comp (bad - 120).

I'm not great with huskies (this is the first I've ever looked at).

I'm gonna have to gauge the owners enthusiasm now, I think, as I've put 15 quid of parts on it and a couple hours of work. I think he may need to show that he'll pay up if I keep working from on - now I've discovered that it aint gonna be a "quick fix".

Will post back on this thread if I make more progress or need more help

Makes sense bud. Didn’t mean to bombard you with stuff lol. Don’t worry about it being a Husky, it’s just a saw. And being that it’s an older one it’s one of the simplest designs to work on.

 

[angelo c]

Matt, shove a few drops of mix down her throat and see if she pops. that will give you a quick and dirty test of compression. with an eye dropper full of mix it should take off and run to full throttle rpm for a sec or two. id have a look at the jug through the muffler and check for scoring or ring wear with 120psi on a "known" tester.

 

[MattG]

I tried testing the compression again.....only 80psi MAX.....think the other tester was broke.

Retried starting it, e.g. squirting gas in throat, changed to different plug, still no pop

So obviously next thing is look at piston, jug, etc.

Tell me fellas, is this meteor piston the correct one for this model?

https://www.ebay.co.uk/itm/Meteor-C...PC2031000-40/172372487107?hash=item2822336bc3

 

[RIDE-RED 350r]

120psi should be adequate for that saw to start and run. Those 136/142 are not high performers. Under 80psi though, thats likely to be a problem.

I'm betting you find a scored piston and seized rings in that saw.

Sequence of events: filter comes off the end of the line, unfiltered fuel is fed to the carb for who knows how long, but long enough to plug up the carb with the debris you found creating a lean condition that ends up scorching the piston and rings.

That should be the correct piston, but do pull the cylinder and see if it's salvageable before ordering a stand-alone piston. You may have a cylinder that's not salvageable

 

[Wonkydonkey]

120psi should be adequate for that saw to start and run. Those 136/142 are not high performers. Under 80psi though, thats likely to be a problem.

I'm betting you find a scored piston and seized rings in that saw.

Sequence of events: filter comes off the end of the line, unfiltered fuel is fed to the carb for who knows how long, but long enough to plug up the carb with the debris you found creating a lean condition that ends up scorching the piston and rings.

That should be the correct piston, but do pull the cylinder and see if it's salvageable before ordering a stand-alone piston. You may have a cylinder that's not salvageable

That’s pritty much what a thought happened to my 026, although I already knew my piston was scored. I just had to find the reason,
http://opeforum.com/threads/ms026-cheapish-rebuild-fix.12696/#post-661503

 

[MattG]

120psi should be adequate for that saw to start and run. Those 136/142 are not high performers. Under 80psi though, thats likely to be a problem.

I'm betting you find a scored piston and seized rings in that saw.

Sequence of events: filter comes off the end of the line, unfiltered fuel is fed to the carb for who knows how long, but long enough to plug up the carb with the debris you found creating a lean condition that ends up scorching the piston and rings.

That should be the correct piston, but do pull the cylinder and see if it's salvageable before ordering a stand-alone piston. You may have a cylinder that's not salvageable

Wow! Thanks for that RR......why the hell does the filter come off the line? (That is so lame!), and is there a way to prevent this occurence in the future?

Well, I got in touch with the owner, he reckons he's good to pay for the carby parts and my time.....when I told him that the CR looked very bad and said I'd need to strip down, check and probably do a Piston rings kit, he was still happy, so that's the next step, when I get a free minute.

However, I'm now anxious about going ahead.......how likely is it (on these saws) for the crank seals to go?

Thing is, that all my tools are more stihl focused, and if I'm gonna need to do the seals I'll need the clutch off, and that's gonna need me to take time out making up a special tool by the looks of it. (Don't want to purchase one right now - wanna keep the budget on this saw down a bit). Also to pressure and vaccuum test this husky motor, I can see there's more work (I guess) to make up a blanking plate (on the intake side) with an attachment for my mityvac.

This will also be my first clam-shell style engine strip.....

So seeing as this thing definitely needs piston kit (at the minimum), what would you fellas recommend? The manual I got suggests, 1) muffler off 2) carb off 3) tank unit, then just unscrew 4 screws from underneath the lump. Is it that simple? What are the pitfalls? Should I just pull the jug up (and presumably all is well), clean up any smears and throw the new piston kit on? Do you guys typically just try to assume the seals are good (I guess if the bearings are bad they won't be....anyway that's a whole new problem...)

Sorry for big essay..just getting my thoughts/concerns down and hoping some of you have got some good recommendations.

 

[RIDE-RED 350r]

As to the fuel filter falling off, only a couple of reasons I can think of that might cause that. 1: very old and deteriorated fuel line or a replacement filter that didn't quite have the right size Barb on it to grip the fuel line sufficiently.

I would not just assume the crank seals are OK. A pressure test now before you tear it down would be a good idea to check those.