Ms200 intake boot

[Flash]

So I've got this ms200t that quit in the cut the other day. It was hard to restart and wouldn't stay running. I popped off the muffler to look at the piston and there was light scoring.

Long story short, I cleaned the cylinder, got new piston assembly and after the pressure test found my intake boot was leaking where it connects to the jug. I put on a different boot (not new but was pretty sure it was good) and it failed the pressure test too. It was better, but still wanted to let out some air.

Is it possible the jug has bad casting that won't let it seal?

I could always get a new boot, but if that won't seal, could I put on some gasket sealer and make it work?

 

[Flash]

Any thoughts?

 

[Chainsaw Jim]

Are you sure that is where it is leaking?

 

[Flash]

Yup. I know the clutch side oil seal is a common culprit but that is not the leak here. I get bubbles around the intake boot where it seats on the jug. It actually took me a while to find it because it wasn't leaking anywhere else.

I also tested without the boot and had the cylinder intake sealed off. When I did this, it held pressure and vaccume steady 3-4 minutes. No movement on the gauge.

 

[stihl saws]

I'd get a new boot and try that first. Does the intake have any burrs or scratches? Some gas resistant sealant should fix that if it does.

 

[Flash]

There is nothing obviously out of the ordinary with it, but I suspect something. I have the original boot that was leaking. I tried a second good used boot that I had lying around and I even pulled third one off another running saw. All failed to hold pressure.

I'm going to do a more thorough inspection of the jug intake and compare it to another I have lying around. If it does have an abnormality, would you still suggest fitting a new boot or just use the old one with some sealant? I've got some dirko ht lying around I was planning to use if it came to that.

 

[Chainsaw Jim]

I'd suggest a new oem flange that holds the boot down. Those things should be a real pita to get down over the boot from being a very tight fit.

 

[rynosawr]

I have an 020T that did the exact same thing as your 200 and I finally just bought a brand new boot for it today and it sealed right up.

The other two used intakes I tried on it weren't nearly as snug going on the flange or when I installed the retaining clip as the new one.

You could try some stiff sealant and it might work ok, but the boot has compressed where the retainer clamps it and you may not be able to put the sealant where you need it for increased tension.

My other suggestion is to wrap the intake flange with some Teflon tape to allow you to tighten up the flange and groove. That should work better than sealant because it is merely adding thickness that won't squeeze out like sealant. Always use a dab of grease on the intake boot and retainer.

My carb flange was really squished and I didn't think it was as good as it needed to be, so I bought the new boot.

 

[angelo c]

How are you sealing off the intake ?

 

[Flash]

How are you sealing off the intake ?

With the boot on, I just put a piece of rubber behind the carb and tightened the carb back down.

When testing with the boot off, I removed the handle. Then I fit a rubber tire tube over the cylinder intake and put a hose clamp around it to seal it.

 

[angelo c]

With the boot on, I just put a piece of rubber behind the carb and tightened the carb back down.

When testing with the boot off, I removed the handle. Then I fit a rubber tire tube over the cylinder intake and put a hose clamp around it to seal it.

make sure you Vaseline around the rubber to get a tighter seal.

 

[stihl saws]

I'd still start with a new boot and go from there. The rubber hardens over time and may not seal as well as it should. Not worth taking a chance on relatively cheap new vs. questionable used parts.

 

[Flash]

Thanks for the advice

 

[stihl saws]

Your welcome. I bought and rebuilt a 200t that was scored from a cracked intake boot. It's just not worth taking a chance on part like that.

 

[Wood Doctor]

Make sure you Vaseline around the rubber to get a tighter seal.

Also, make sure that the boot's machine screw and nut that holds the clamp are tight. I have run unto loose ones.

 

[angelo c]

Also, make sure that the boot's machine screw and nut that holds the clamp are tight. I have run unto loose ones.

Doc, the last few 200ts I've done didn't have a clamp at all, there is just a plastic "cap" that holds it down. Weird. The little sumbeaches go together fast once ya done a few.

 

[rynosawr]

The cap is what tensions the boot, if the boot is not too loose and too thin to be tightened by the square retainer cap.

Again, the method of Teflon tape will most likely give the best results when used with the plastic square retainer cap.

 

[Flash]

Again, the method of Teflon tape will most likely give the best results when used with the plastic square retainer cap.

How would the Teflon hold up to heat?

 

[juttree]

Try the retainer off of the running saw.

 

[rynosawr]

How would the Teflon hold up to heat?

I think most teflon tape is rated for 300 degrees Fahrenheit and some go as high as 400 degrees from what I can read. Your 2 stroke engine won't see any temps above 200F usually and they start having problems if they go over 225F.


Since the Teflon tape will be on the intake (cooler side of the engine), it shouldn't be as hot as the max head temp reached.

You are really only needing to wrap the teflon into the groove of the aluminum casting of the intake to tighten up where the boot fits into the groove.

It should make a good difference in how tight the square retainer fits once you get several wraps of teflon tigthly wound up on there. You can measure the groove before teflon and after and see how much it takes to make the intake boot stop leaking when tested.