Possible air leak in 365. Thoughts?

[BigDaddyR]

Okay so after doing the modification for the tranfer baffles to my 365XT I can't seem to get it to idle steady and seems like it races then when warm idles better. Has cut okay and made good power but from reading on here I know it can be seriouls not good for your saw and want to fix the issue. The other day I took a quick look at it with the top cover off and found the intake boot clamp about 4 turns loose. Not sure if it vibrated loose or I left it loose. I really thought I had it tightened. Does this need thread locker on it to be sure or do they typically hold well?

Started it and still seems to pick back up speed and race after bringing down from High idle. I don't remember it doing this before so will assume it has a leak. It does seem to slow down when turned on either side but does not die. When I first did the mod and then got it tuned by the dealer then it did die when turning it on it's side

When grinding the transfer covers I knicked the side raised edge bevels for lack of a better way to put it but at the time didn't think it would be an issue as it has an oring type gasket/seal in the transfer cases.

The other thing it could be is the base gasket which looked in very good shape when I put it back together.

I bought some Permatex Anerobic Gasket Sealer based on my dealer recommendation and some things I read on here. Can the sealer be used to seal the transfer covers along with the orings, do I need new transfer covers off of a 372, or do I need to rebuild the "channels" on the covers with JB weld.

As far as sealing the base gasket goes does it make any sense to remove the base gasket and just use the sealer that I got. It seems that a lot of people here have measured the squish and have had sufficient room to remove the base gasket. Are tolerances consistent enough with Husqvarna parts manufacturing to trust that I could do so without measuring squish? Just questions here. I don't have to take shortcuts but don't have the tools to measure at this time. I'm okay with just sealing the gasket and putting it back on. I don't care much about any extra compression. I just want to fix my saw and have it run right.

Thanks for any thoughts. I'm going out to see if I can narrow down the leak.

 

[watsonr]

Only a pressure/vacuum test will determine if it has an air leak. Also is the carb adjusted correctly? Using an old gasket is never a good idea and yours sounds like its in need of help.

If it has an air leak, you'll burn it up if your not careful.

The only way to be sure of squish is to measure. Maybe someone here is close to you to help with the right tool?

 

[screamin350]

Discontinue use until you can make or obtain a vac/press. tester. Could possibly be the old base gasket, definitely don't want to keep using it though. I believe there are several threads on here about making a homemade tester.

 

[Roanoker494]

Not sure how those baffles are sealed but that is where I would start since that is what you had off last, like Watson mentioned you need a vac/pres test. Also not a good idea to reuse gaskets, they may look okay but they kind of harden up and will not seal after removal. You may be able to find a local shop that can do the vac/pres test, my local Husky shop will do it for $20.

 

[HuskStihl]

Any pictures of the modified/injured covers? I can't wrap my head around what they now look like. I bet some members have burnt 372 cylinders you could get covers from. If I understand right the restrictor plate is in the transfer cover, so 2 birds with one stone so to speak. Regarding the base gasket, there is probably only a 5% chance your saw would have less than 0.018 squish without the gasket, but even if ur a gambling man (i wouldnt be with my saw), you said u'r happy with the torque, so no real reason to bother. If I remember, nmurph knows a lot on this subject and hopefully he'll be along soon! Sorry to hear it's misbehaving, I know you like that saw

 

[BigDaddyR]

Base gasket came of to do the modificiation to the transfer baffles also. Sounds like I either need a new gasket or to measure the squish and seal it. Will need to see if the baffles are leaking 1st as I don't want to seal up the clinder again unless I send it out to get ported etc. If I decide to try to delete the gasket I'll see if someone is local and wants to have fun with it or I will by the measuring tool and check it per the vidoe I saw by a member.

They sell the vacuum/pressure test tools at the local stores as well as I'm sure the sponsors on here also sell them. Here's a picture of the baffles but it's a little hard to see.

View attachment 281276

 

[HuskStihl]

Base gasket came of to do the modificiation to the transfer baffles also. Sounds like I either need a new gasket or to measure the squish and seal it. Will need to see if the baffles are leaking 1st as I don't want to seal up the clinder again unless I send it out to get ported etc. If I decide to try to delete the gasket I'll see if someone is local and wants to have fun with it or I will by the measuring tool and check it per the vidoe I saw by a member.

They sell the vacuum/pressure test tools at the local stores as well as I'm sure the sponsors on here also sell them. Here's a picture of the baffles but it's a little hard to see.

View attachment 281276

I think you should be able to get those to seal. Maybe new gaskets permatex everything, then pressure test?

 

[BigDaddyR]

Any pictures of the modified/injured covers? I can't wrap my head around what they now look like. I bet some members have burnt 372 cylinders you could get covers from. If I understand right the restrictor plate is in the transfer cover, so 2 birds with one stone so to speak. Regarding the base gasket, there is probably only a 5% chance your saw would have less than 0.018 squish without the gasket, but even if ur a gambling man (i wouldnt be with my saw), you said u'r happy with the torque, so no real reason to bother. If I remember, nmurph knows a lot on this subject and hopefully he'll be along soon! Sorry to hear it's misbehaving, I know you like that saw

The baffles was on the covers and I ground them off. They are sealed by black semi rectangular orings and the covers have a ridge that is built up them that goes on the inside of the oring if I remember correctly.

Good news is I looked at the piston the other day and it still looks brand new so I don't think it's done any damage at this point which I'm very happy about.

You're right I llove this saw. It's upsetting to me to have made this mistake in the first place but what would be worse is not getting some insight and thoughts from the members here like you and allowing it to get worse. I will figure it out, with help if needed, and I will get it back to right. I guess if we don't make mistakes then we don't learn from them and we can't get better.

Three months or so ago I didn't know anything about 2 strokes. Now I'm taking them apart and learning how to fix them because of the need and this site. Like my step sons unit in the Army says, Always Forward.

 

[BigDaddyR]

Okay so I decided to just go ahead and man up and check the squish on it to remove the base gasket. I've seen the videos and read some of the threads so wish me luck.

As was said I got the Permatex Anerobic gasket sealer. Any tips on how to use it properly on this application?

Also was going to use it on the transfers inside the oring gaskets but not really the best solution in my mind.

Anyone have a set of 272/372 transfer covers that their willing to part with? If so PM me please.

 

[HuskStihl]

I really like the yamabond 4, but if the permatex is not degraded by oil or gas, and tolerates heat, it shouldn't be a problem. I ran a thin bead where the gasket was, being careful to not get any into the cylinder bolt holes, then used a large flat screwdriver to flatten and thin the layer. Replace the jug, tighten the bolts, and leave it for 24 hours. My 385xp picked up 25psi of compression and a pretty pronounced increase in torque doing this. I have many hours on the saw since, with no signs of a leak/problem. Hope it goes smooth and easy

 

[BigDaddyR]

Thanks man. The tech at my dealer said the Anerobic stuff is good. I know it wasn't cheap at like $13.00 and does say on the package good for metal to metal esp aluminum applications. Maybe I'll give it a go tonight.


Sent from my iPhone using My Fingers

 

[HuskStihl]

Probably goes without saying, but be really careful to not get any in the cylinder

 

[screamin350]

Squeeze out a narrow bead, smear it around evenly with your finger. Good thing with the anaerobic sealer is if you get any in the cyl, it will harmlessly dissolve over time (thats the theory anyways). And of course let it set up for a good 24, test of course afterwards.

 

[BigDaddyR]

Okay so I finally got a pressure tester and rigged up some block offs for the xhaust and intake on my 365. While testing it dropped from 10lbs to 5lbs in about 10 seconds. The decompression valve is leaking. Teflon taped the threads and now better but still leaking at the valve itself. Now takes 30 seconds to leak down to 5lbs. Is this valve bad? Should it be replaced under warranty? Saw is less than a year old.


Sent on the fly.

 

[mdavlee]

Either buy a new valve or just put a bolt in there and not worry about the valve leaking again.

 

[BigDaddyR]

Either buy a new valve or just put a bolt in there and not worry about the valve leaking again.

Guess I'll have to hit the hardware store. Local big box stores only had the 10mm bolts about 1" long which is too much. My dealer is a hardware store so I'll see if they'll warranty it. Need some other parts as well.

 

[Mastermind]

I think your carb is just out of adjustment. Start at 2 turns out on the XT......

 

[BigDaddyR]

I think your carb is just out of adjustment. Start at 2 turns out on the XT......

No adjustments fixed the problem which is why I pressure tested it. Found the detent leaking and also the rubber baffle/guide that goes across carb on the carb going into intake boot side, one side was folded over and pinched when I took it apart and I could see the outline of it on the intake boot. I think between those two things are where most of my issues lie.

Will get a valve or better bolt than I could find today and then tune it with your starting points.

Thanks for the settings.