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SRM 230 Trimmer

#1

PTmowerMech

PTmowerMech

Cleaned out the old carb, and it started and ran fine after installation. A week later, customer comes to pick it up and it started running like crap. So I got a new one from Stens. Like the other, it started and ran fine for about 20 minutes. Decided to do some trimming with it, it died at full throttle. I couldn't tell if it sounded like it flooded or ran out of fuel.
Anywho, not it'll only start on fuel poured directly into the carb. Primer fills up fine. The carb holds 7lbs for at least 2 minutes. Compression is over 120lbs.

What plugs up in these cube carbs, that don't allow them to get fuel besides the screen and needle?


After pulling many MANY times, plug is just barely wet. I mean just barely.


#2

Hammermechanicman

Hammermechanicman

Things to check. Tank vent, crankcase bolts, remove carb and put a drop of oil in the impulse hole and pull rope and watch for air pulsing in and out of the hole. check carb to engine gaskets. new fuel filter?


#3

PTmowerMech

PTmowerMech

Fly wheel key is good. Tank vent is good. Ports are clear enough. 4 bolts under flywheel were pretty loose. at least by 1/4 turn. Filter has been blown out.


#4

tom3

tom3

Dumb question but I'll ask anyway. Did you pull the filter ouf of the tank and check the tubing for cracks?


#5

StarTech

StarTech

Pressure and vac test the crankcase.


#6

PTmowerMech

PTmowerMech

tom3 said:
Dumb question but I'll ask anyway. Did you pull the filter ouf of the tank and check the tubing for cracks?
Click to expand...
New fuel lines and gromit. Sprayed some sea foam in the filter when I cleaned the first carb. Then blew it out a few minutes later.


#7

PTmowerMech

PTmowerMech

StarTech said:
Pressure and vac test the crankcase.
Click to expand...


Question: if you to a compression test and get 120lbs, and it holds, doesn't that eliminate the possibility of crankcase leaks? I'm asking because I don't have a way to test crankcase on 2 cycles.


#8

PTmowerMech

PTmowerMech

FIXED!!!!!!!!!

I backed the low idle out all the way, and darn thing fired right up.

I got to thinking that since it would fire up on mix poured into the carb, but die out as soon as the fuel was all gone, then it almost has to be getting fuel to the plug. So I backed it out, thinking maybe something may be clogging up the low idle jet. Well, turns out, that's about where this carb needed to be, to get the right amount of fuel to the plug.
I suppose there's something wrong with this carb. But, it's been idling for about 10 minutes. And the response time is quick.

Thanks everyone for their input and advice.


#9

R

Rivets

Check the crankcase seals, one or both may be bad.


#10

PTmowerMech

PTmowerMech

Rivets said:
Check the crankcase seals, one or both may be bad.
Click to expand...

I don't have a pressure tester for those. For future reference, I'd have to open the crankcase to check them, right? That doesn't seem right.


#11

Hammermechanicman

Hammermechanicman

No, you need something like this.
www.ebay.com

Hand Held 21pcs Vacuum Pressure Pump Tester Brake Fluid Bleeder Bleeding Kit | eBay

Find many great new & used options and get the best deals for Hand Held 21pcs Vacuum Pressure Pump Tester Brake Fluid Bleeder Bleeding Kit at the best online prices at eBay! Free shipping for many products!
www.ebay.com
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.


#12

Scrubcadet10

Scrubcadet10

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


#13

Hammermechanicman

Hammermechanicman

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
www.ebay.com

pressure vacuum tester carb flange FOR Stihl Chainsaw # 5910 850 4207 ----UP662 | eBay

Requires the use of other parts, such as a pressure vacuum pump, tubing, exhaust flange or block and spacers and nuts.
www.ebay.com


#14

B

bertsmobile1

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.


#15

PTmowerMech

PTmowerMech

Hammermechanicman said:
No, you need something like this.
www.ebay.com

Hand Held 21pcs Vacuum Pressure Pump Tester Brake Fluid Bleeder Bleeding Kit | eBay

Find many great new & used options and get the best deals for Hand Held 21pcs Vacuum Pressure Pump Tester Brake Fluid Bleeder Bleeding Kit at the best online prices at eBay! Free shipping for many products!
www.ebay.com
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.
Click to expand...

I have this one.
www.ebay.com

Mity-Vac MV8500 Silverline Elite Automotive Test Kit. 2-in0 Vacuum & Pressure! | eBay

SILVERLINE ® ELITE AUTOMOTIVE TEST KIT. • Silverline Elite Hand Vacuum/Pressure Pump. + Produces vacuum or pressure at the turn of a switch. • 12 Vacuum Cap Plugs. • Vacuum Line T-Adapter. • Master Cylinder Refill Kit (model no. ).
www.ebay.com


#16

PTmowerMech

PTmowerMech

bertsmobile1 said:
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.
Click to expand...


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


#17

Hammermechanicman

Hammermechanicman

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.


#18

PTmowerMech

PTmowerMech

Hammermechanicman said:
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.
Click to expand...

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


#19

Hammermechanicman

Hammermechanicman

Now you are an expert 2 stroke mechanic


#20

PTmowerMech

PTmowerMech

Hammermechanicman said:
Now you are an expert 2 stroke mechanic
Click to expand...

WOO HOO.. I'm back up to a 4. lol


#21

Hammermechanicman

Hammermechanicman

Gonna buy me a book and get me learned up. That should get me up to a 3 or at least a 2 1/2.


#22

Scrubcadet10

Scrubcadet10

Hammermechanicman said:
Gonna buy me a book and get me learned up. That should get me up to a 3 or at least a 2 1/2.
Click to expand...
Book? what happened to stone tablets?


#23

Hammermechanicman

Hammermechanicman

Scrubcadet10 said:
Book? what happened to stone tablets?
Click to expand...
I don't really read them words. I just look at the pictures. Hard to see the pictures on the stone tablets.


#24

Scrubcadet10

Scrubcadet10

Hammermechanicman said:
I don't really read them words. I just look at the pictures. Hard to see the pictures on the stone tablets.
Click to expand...
Oh look, a Cave man using a Club and pry stick to remove a flywheel....
t3609.gif


#25

Hammermechanicman

Hammermechanicman

They don't call me Hammer mechanic for nuttin' . When in doubt just beat on it till it works. Even a cave man can do it.


#26

Scrubcadet10

Scrubcadet10

Hammermechanicman said:
They don't call me Hammer mechanic for nuttin' . When in doubt just beat on it till it works. Even a cave man can do it.
Click to expand...
just beat on it till it works, or if you damage it too bad in the process, buy a new one ;)


#27

Hammermechanicman

Hammermechanicman

Shhhhh. Don't tell anyone that is how i make a profit. Markup on some parts that just can't be fixed for some reason.


#28

PTmowerMech

PTmowerMech

Scrubcadet10 said:
Book? what happened to stone tablets?
Click to expand...

Those are too heavy.


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