SRM 230 Trimmer

Hammermechanicman

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No, you need something like this.
It does both pressure and vacum testing. When you get 120psi that is secondary compression and does not do any testing of primary compression. To test that you seal up the engine and apply about 7 psi pressure and see if it holds then apply a vacuum and see if it holds. Primary and secondary compression are tested completely differently. A bad crank seal or a torn intake boot has destroyed many chainsaw pistons and cylinders due to running lean. If you are going to get serious about fixing 2 strokes and especially chainsaws you really need some special tools. You may not get into splitting crankcases and pressing bearings but you need to learn to pressure and vac test.
 

Scrubcadet10

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Taryl has a good segment in his most recent video about pressure testing.
 

Hammermechanicman

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I saw that. Not a fan of how he does it as it does not test the intake boot. I have the stihl carb adapters so it is easy. I clamp a piece of rubber under the muffler and install the carb adapter and test. Everyone has their method. Whatever works
 

bertsmobile1

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You loosen the carb & the muffler
Shove some thick rubber sheeting across the holes then tighten down on them to seal both inlet & exhaust .
Set the piston to BDC insert the pressure fitting ( modified spark plug ) into the spark plug hole & start pumping
The crankcase void is a lot bigger than most think so you might need 100 or so strokes to get it up to about 20 PSi
It should hold that indefinately
Release pressure then switch to vacuum you should be able to pull a good vacuum and again it should hold
I think I get about 10 or so strokes for vacuum .

If the power head has a remote impulse line then you can hook up to that .

I think Tiny Tach have the completer set up minus the vacuum/ pressure pump in their tools section .
I have made a couple of blanking plates that replace the carb where the carb bolts directly to the cylinder .
A couple of spacer tubes to replace the entire carb & air box and a pair of wing nuts .

Pretty sure It has been suggested before, but Joe Pace ( ex Husqvarna tech school ) did a series on 2 stroke diagnosis where he goes through pressure testing in painfully methodical detail .
Just today I replaced a leaking tanks grommet on one trimmer , a leaking fuel cap on a star picket driver and a broken fuel line on a Talon chain saw .
$ 45 a piece + parts and less than 10 minutes a hit .
Should every day be so easy.

The chainsaw clutch tools have been really handy & to my shameI did buy one of the brass adapters ( should have turned one up myself ) and glad I did as the long taper means it fits every carb hose so is peminently on the end of the pump .
SO it is off with the fuel lines at the carb, golf T in the inlet line & pump the tank to 7 PSI then vacuum test
Then pull the T out and a couple of strokes to check what sort of flow is coming out through the filter
Slip a scrap piece of tube on each of the carb spiggots and pressure / vacuum test the carb.
Again less than 5 minutes .
At least 1/3 of the hand helds that come in have tank problems that previously I had not found till after I had spent hours trying to tune them properly.
 
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PTmowerMech

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No, you need something like this.
It does both pressure and vacum testing. When you get 120psi that is secondary compression and does not do any testing of primary compression. To test that you seal up the engine and apply about 7 psi pressure and see if it holds then apply a vacuum and see if it holds. Primary and secondary compression are tested completely differently. A bad crank seal or a torn intake boot has destroyed many chainsaw pistons and cylinders due to running lean. If you are going to get serious about fixing 2 strokes and especially chainsaws you really need some special tools. You may not get into splitting crankcases and pressing bearings but you need to learn to pressure and vac test.

I have this one.
 

PTmowerMech

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You loosen the carb & the muffler
Shove some thick rubber sheeting across the holes then tighten down on them to seal both inlet & exhaust .
Set the piston to BDC insert the pressure fitting ( modified spark plug ) into the spark plug hole & start pumping
The crankcase void is a lot bigger than most think so you might need 100 or so strokes to get it up to about 20 PSi
It should hold that indefinately
Release pressure then switch to vacuum you should be able to pull a good vacuum and again it should hold
I think I get about 10 or so strokes for vacuum .

If the power head has a remote impulse line then you can hook up to that .

I think Tiny Tach have the completer set up minus the vacuum/ pressure pump in their tools section .
I have made a couple of blanking plates that replace the carb where the carb bolts directly to the cylinder .
A couple of spacer tubes to replace the entire carb & air box and a pair of wing nuts .

Pretty sure It has been suggested before, but Joe Pace ( ex Husqvarna tech school ) did a series on 2 stroke diagnosis where he goes through pressure testing in painfully methodical detail .
Just today I replaced a leaking tanks grommet on one trimmer , a leaking fuel cap on a star picket driver and a broken fuel line on a Talon chain saw .
$ 45 a piece + parts and less than 10 minutes a hit .
Should every day be so easy.

The chainsaw clutch tools have been really handy & to my shameI did buy one of the brass adapters ( should have turned one up myself ) and glad I did as the long taper means it fits every carb hose so is peminently on the end of the pump .
SO it is off with the fuel lines at the carb, golf T in the inlet line & pump the tank to 7 PSI then vacuum test
Then pull the T out and a couple of strokes to check what sort of flow is coming out through the filter
Slip a scrap piece of tube on each of the carb spiggots and pressure / vacuum test the carb.
Again less than 5 minutes .
At least 1/3 of the hand helds that come in have tank problems that previously I had not found till after I had spent hours trying to tune them properly.


I have some old inner tubes that I could cut to fit. That would work, to seal off the intake and exhaust ports, right?
 

Hammermechanicman

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Yes, that will work. I use pieces of EDPM rubber from a pond liner that are about 3 times thicker than inner tube. Got about a half dozen different size strips. I like it better than inner tube. You Just need 14mm and 10mm sparkplug adapters.
 

PTmowerMech

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Yes, that will work. I use pieces of EDPM rubber from a pond liner that are about 3 times thicker than inner tube. Got about a half dozen different size strips. I like it better than inner tube. You Just need 14mm and 10mm sparkplug adapters.

I think I have them. I have the ones that fit into the normal plug holes and the one smaller one. Thanks
 
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