346xp lean running problem.

[2broke2ride]

This is a customers saw. About a year ago, I did a mild port job, muffler mod, base gasket delete, and new ring. The saw ran awesome for about 3 months then started acting like it had an air leak. Quick and dirty test with some carb cleaner indicated a leak in the inake boot area so I tore it back down and replaced the intake boot, pulse line, and factory metal pinch clamp with a worm clamp. Fast forward to now. It is doing the same thing, carb clean test shows a leak in the intake area but it passes a pressure and vac test with flying colors which suggests to me that the carb isn't sealing to the intake and my rubber block off is sealing it up.
What gives here? Is there a common problem that I dont know about? Warped plastic divider maybe? Gimme some ideas guys. This guy is an arborist and needs his saw back asap.

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[hoskvarna]

This is a customers saw. About a year ago, I did a mild port job, muffler mod, base gasket delete, and new ring. The saw ran awesome for about 3 months then started acting like it had an air leak. Quick and dirty test with some carb cleaner indicated a leak in the inake boot area so I tore it back down and replaced the intake boot, pulse line, and factory metal pinch clamp with a worm clamp. Fast forward to now. It is doing the same thing, carb clean test shows a leak in the intake area but it passes a pressure and vac test with flying colors which suggests to me that the carb isn't sealing to the intake and my rubber block off is sealing it up.
What gives here? Is there a common problem that I dont know about? Warped plastic divider maybe? Gimme some ideas guys. This guy is an arborist and needs his saw back asap.

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Sometimes if delete the gasket it will lower the intake boot and put undo stress on it at the carb or jug
Had that happen,it will push up on it and pulls it away from bottom of carb
Idk just something to check.


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[Bob Hedgecutter]

So you did the soapy water thing to establish exactly where the leak was?
No burrs or anything cutting through the rubber after a bit of work?

I guess it could be the angle of the lowered cylinder versus the original of the intake manifold- have never seen it personally, but guess it might happen. Maybe delete the plastic surround of the manifold and clamp the rubber direct to the cylinder- eliminate the rigidity of the plastic?

 

[2broke2ride]

So you did the soapy water thing to establish exactly where the leak was?
No burrs or anything cutting through the rubber after a bit of work?

I guess it could be the angle of the lowered cylinder versus the original of the intake manifold- have never seen it personally, but guess it might happen. Maybe delete the plastic surround of the manifold and clamp the rubber direct to the cylinder- eliminate the rigidity of the plastic?

There are no leaks when doing a conventional pressure test but if I spray the intake area with carb cleaner with the engine running it kills the engine so I know there is a leak there somewhere. I am assuming it must be right at the carb and the piece of rubber I am using to.block.the intake to pressure is sealing the leak.
I cant eliminate the plastic piece completely, it provides the impulse passage to the carb.

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[Bob Hedgecutter]

There are no leaks when doing a conventional pressure test but if I spray the intake area with carb cleaner with the engine running it kills the engine so I know there is a leak there somewhere. I am assuming it must be right at the carb and the piece of rubber I am using to.block.the intake to pressure is sealing the leak.
I cant eliminate the plastic piece completely, it provides the impulse passage to the carb.

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No, but you can get rid of the bit that the metal clamp goes around and just clamp the rubber.
So you are certain the threads are not flogged out for the carb mounting bolts? Leak at the back of the carb they will if those are not holding.

 

[PogoInTheWoods]

Test it with the carb in place by using a piece of fuel hose as your injection point packed in a glob of plumber's putty packed into the carb intake..., or maybe just in the air filter elbow. Obviously block off the exhaust. Use light air pressure and soapy water or a cheap cigar and blow smoke into it. You'll find your intake leak if indeed there is one. Could even be the carb body badly worn somehow at the throttle plate shaft. Then again, it could be an intermittent leak that only occurs with the saw running.

As for the intake bulkhead going from the plastic clamp to metal, I'd strongly advise against eliminating the plastic piece altogether in favor of just clamping the boot. It would eliminate support for the impulse passage fitment.

Here's how I approach the clip conversions..., (though this is a 357). After removing the tabs, I grind the ribs around the circumference as well for a nice snug fit. The metal clamp itself is an adjustable small end CV boot crimp clamp. Just crimp with dikes or get the specific crimp tool for em. Done several. Never had one fail.

​

 

[2broke2ride]

So I am an idiot, after all of that it is always the simple things you overlook. Dont know why I skipped the carb. The inlet screen in the carb was totally plugged with crap. Cleaned it, reassembled, checked the fuel line, and added a new fuel filter and it runs like a top.

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[cuinrearview]

So I am an idiot, after all of that it is always the simple things you overlook. Dont know why I skipped the carb. The inlet screen in the carb was totally plugged with crap. Cleaned it, reassembled, checked the fuel line, and added a new fuel filter and it runs like a top.

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I can't remember the last build on my bench that a carb kit wasn't the first item ordered.

 

[2broke2ride]

I can't remember the last build on my bench that a carb kit wasn't the first item ordered.

Carb was kitted when I did the original build about a year ago. I can see no reason all that trash made it past the filter, unless the filter fell off at some point and was later replaced.

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[cuinrearview]

Carb was kitted when I did the original build about a year ago. I can see no reason all that trash made it past the filter, unless the filter fell off at some point and was later replaced.

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A year of ****** corn gas can ruin cheap Chinese diaphragms. A $10 or less OEM kit is cheap insurance and the first place I look because you don't know how a customer handles their equipment after it leaves your shop. From other posts you've made I'm assuming you used bottom dollar fuel lines and kit for the carb?

 

[2broke2ride]

A year of ****** corn gas can ruin cheap Chinese diaphragms. A $10 or less OEM kit is cheap insurance and the first place I look because you don't know how a customer handles their equipment after it leaves your shop. From other posts you've made I'm assuming you used bottom dollar fuel lines and kit for the carb?

I think you may have me confused with someone else. I almost always use OEM carb kits, I've had too many fitment problems with aftermarket kits. As far as fuel line goes, I usually use genuine Tygon, but they dont make a size that fits Huskys well so I use OE fuel line in these.

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[RED-85-Z51]

Ive seen alot of inlet screens plugged up on stuff that i really couldnt explain beyond the filter is breaking down internally.

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[cuinrearview]

I think you may have me confused with someone else. I almost always use OEM carb kits, I've had too many fitment problems with aftermarket kits. As far as fuel line goes, I usually use genuine Tygon, but they dont make a size that fits Huskys well so I use OE fuel line in these.

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Well, with a new wrecked saw on the bench we only have to figure out what's wrong. With one we sent out it's easy to blame the user but the cause still has to be troubleshot. What are you thinking is wrong?

 

[cuinrearview]

Ive seen alot of inlet screens plugged up on stuff that i really couldnt explain beyond the filter is breaking down internally.

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It would be tough for me to believe a year of regular use with good fuel system parts could break an OEM filter down. Hell, the chilters could probably even live.

 

[2broke2ride]

Well, with a new wrecked saw on the bench we only have to figure out what's wrong. With one we sent out it's easy to blame the user but the cause still has to be troubleshot. What are you thinking is wrong?

I have no good explanation unless, like I said, the fuel filter fell off at some point and was later replaced. The screen was plugged with what looked like sawdust. This guy puts his saws through hell, anything is possible. His guys try to work on them too so for all I know they may have swapped the carb for some unknown reason. He has at least 3 of these saws as parts saws for various reasons.
All I know is, it's fixed now. The filter is new, there is a fresh kit in the carb, it passes pressure and vac test, tank vent is working as it should, fuel line passes pressure test, and compression is good (made it to 160 on my guage and was struggling to hold the saw down lol)

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[RED-85-Z51]

Well, with a new wrecked saw on the bench we only have to figure out what's wrong. With one we sent out it's easy to blame the user but the cause still has to be troubleshot. What are you thinking is wrong?

Some people are just hard on stuff. I do a couple dozen commercial accounts year round...the equipment is all generally the same...Echo Trimmers and edgers, Stihl Blowers, Toro and Hustler Z mowers. They all stay equally busy..but you'll have 2 companies that go thru flexible cables and clutches..and no one else does. Most of the echo trimmers only ever need normal maintenance...but one guy will inevitably come in with a 6 month old trimmer..exhaust cover melted off...handle held on with duct tape. One fella...i rebuild his hustler spindles 3x a year because he refuses to replace his blades when needed. I dont ever count out some weird off the wall stuff customers may have done to equipment. Hell i rebuilt an 044 that got straight gassed. I broke it in...2 tanks. He picks it up..and immediately does the same thing. Got his cans mixed up..put the mix oil in his can marked 100% gas and his helper put straight gas in the saw.

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[cuinrearview]

For the most part this is a hobby for me so I like to keep it fun and not take work. I don't see patterns, most of the stuff I work on has been on a shelf for a while whether it's in someone else's garage or the repair shop or dealer that has had enough and sends it home with me. Then it usually sits around here until it gets it's turn on the bench. I usually have no history or symptoms and have to start from scratch on each one. Maybe that's an advantage. It's fun for me to figure out why someone quit using something.

 

[grizz55chev]

For the most part this is a hobby for me so I like to keep it fun and not take work. I don't see patterns, most of the stuff I work on has been on a shelf for a while whether it's in someone else's garage or the repair shop or dealer that has had enough and sends it home with me. Then it usually sits around here until it gets it's turn on the bench. I usually have no history or symptoms and have to start from scratch on each one. Maybe that's an advantage. It's fun for me to figure out why someone quit using something.

I have a check list I do, first thing on 2 strokes is pull the muffler to check the piston, then I go from there. If it’s a pro level saw, I’ll put more time into it, weedeaters I try to avoid as they are usually cooked and cheap to replace. Its a hobby for me as well.

 

[RED-85-Z51]

For the most part this is a hobby for me so I like to keep it fun and not take work. I don't see patterns, most of the stuff I work on has been on a shelf for a while whether it's in someone else's garage or the repair shop or dealer that has had enough and sends it home with me. Then it usually sits around here until it gets it's turn on the bench. I usually have no history or symptoms and have to start from scratch on each one. Maybe that's an advantage. It's fun for me to figure out why someone quit using something.

The diagnostic is the fun part...pacing back what caused what until you find your problem. Sometimes you end up with user error.

Example. Troy Bilt Pony rider...variable speed belt drive. I put on new belts..a quality aftermarket brand ive used for many years. 3 months...shredded. He blamed me. Its out of any warranty period...but i offered to replace the belts for just labor...using the same belts. 4 months...shredded. I had obviously already inspected the pulleys and variator sheave. The tractor was newer...only a year old. So i ordered oem belts...but i offered to pick it up...i wanted to see his yard.

Be damned...his yard was a hill...and one of those tow behind powered vacuum carts was sitting next to it in his garage.

I told him...im putting on new belts...you don't have the right mower. He sold it..got a nice D140 Deere and hasnt had any problems in 3 seasons.

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[2broke2ride]

For the most part this is a hobby for me so I like to keep it fun and not take work. I don't see patterns, most of the stuff I work on has been on a shelf for a while whether it's in someone else's garage or the repair shop or dealer that has had enough and sends it home with me. Then it usually sits around here until it gets it's turn on the bench. I usually have no history or symptoms and have to start from scratch on each one. Maybe that's an advantage. It's fun for me to figure out why someone quit using something.

I am still relatively new to doing this as a side business. I am trying to work out a diagnostic sequence that works. On my personal hobby saws I likely would have done the carb first but on those, I'm going to fix it anyway regardless of time or price. On a paying customers saw I dont want to throw parts or labor at it for them to bail on it and I eat it. Most of the customer stuff I see is consumer grade clamshell saws so not worth putting a ton of time into.

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