SRM-210 Boggs After Running - Fix With Turning Sideways or Opening Tank Cap

ihredneck

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  • / SRM-210 Boggs After Running - Fix With Turning Sideways or Opening Tank Cap
SRM-210 older model with the double ring piston and no spark arrestor in the exhaust.

Condition:
Starts up as easy as my PAS-266 and after operating for about 20-30 minutes in thicker grass it will start to bog down a bit. I can fix this one of two ways, 1. quickly rotate the trimmer 90 degrees as if I was going to edge with it and then back to normal position and the RPM and power will come back 2. loosen the gas cap.
Eventually after 45 minutes to an hour of trimming the rotating fix doesn't work very well. If I loosen the gas cap after about the same amount of time of operating 'the fix' will stop working and the trimmer will start to bog down until I re-tighten the gas cap.

Here is what has been done to the trimmer (the bogging issue was an issue before and after these repairs have been performed for miscellaneous reasons)
- new carburetor
- all new gaskets/seals (intake, crankcase, crank seals, head gasket)
- was told that it got a new vent/fuel lines and filter with the carburetor replacement
- checked by applying vacuum the vent actually allowed air into the fuel tank
- checked for carbon build up on the exhaust port
- new upper piston ring

I'm quite perplexed because I figure if it was a air leak that all the gaskets/seals being replaced would have solved it and if the vent was the problem, why does leaving the gas cap loose only work for so long until it needs to be re-tightened?
 
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jp1961

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  • / SRM-210 Boggs After Running - Fix With Turning Sideways or Opening Tank Cap
According to my Lawn-Boy mechanics handbook a loss of power is due to these problems (I know not an Echo, but still a 2 stroke).
Restricted exhaust port and/or muffler (you checked that).
Worn or damaged crankshaft oil seals (you replaced those).
Scored damaged or frozen piston rings (you replaced that).
Carbon scored piston/cylinder walls (????)

What's the compression reading at? I've checked several small "weedie" engines and the best reading I've gotten was around 80 psi.

One more item you could check is the pulse port for the carb. Remove the carb and check the small hole under the carb hole opening for any dirt or foreign objects. Was the carb gasket installed 180 degrees wrong possibly blocking this small hole? Maybe a small piece of gasket or gasket sealer is floating around in the crankcase temporarily blocking the pulse port?

Regards

Jeff
 
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jp1961

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  • / SRM-210 Boggs After Running - Fix With Turning Sideways or Opening Tank Cap
I just checked parts tree.com,,,new cylinders are available, but depending on your exact model number range from 65 to 95 dollars. Not sure if it's worth it.

Regards

Jeff
 

ihredneck

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  • / SRM-210 Boggs After Running - Fix With Turning Sideways or Opening Tank Cap
I will have to check the pulse port to verify if it is blocked or the gasket is on wrong or misaligned.
I can't check compression very well because my gauge has a long hose on it and for these little engines it loses some of the actual pressure due to the hose.

As far as the cylinder I had looked at it and it didn't looked scored but I never ran my nail on it to check.
 

Telesis

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  • / SRM-210 Boggs After Running - Fix With Turning Sideways or Opening Tank Cap
Have you tested the vent plug by connecting a piece of hose and blowing or sucking through it to make sure it's not blocked? I'd do the same with the fuel inlet filter stone just to be sure. I doubt it's a compression issue if you can run it for the periods you state but for giggles and grins, was the cylinder wall in nice smooth shape when you replaced the ring?

Because of the way you described it, it sounds like someone other than you did the fuel lines and filter. It's worth double checking that the inlet and outlet fuel lines are connected the right way on the carb. I doubt this is the problem but you want to establish a proper baseline.
 

ihredneck

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  • / SRM-210 Boggs After Running - Fix With Turning Sideways or Opening Tank Cap
Have you tested the vent plug by connecting a piece of hose and blowing or sucking through it to make sure it's not blocked? I'd do the same with the fuel inlet filter stone just to be sure. I doubt it's a compression issue if you can run it for the periods you state but for giggles and grins, was the cylinder wall in nice smooth shape when you replaced the ring?

Because of the way you described it, it sounds like someone other than you did the fuel lines and filter. It's worth double checking that the inlet and outlet fuel lines are connected the right way on the carb. I doubt this is the problem but you want to establish a proper baseline.

I had pulled the vent and looked to make sure it wasnt plugged and that i could suck air through it. I will probably swap out the filter/vent assembly with the one on my PAS-266 just to be sure. From what i recall the cylinder was in good shape and didn't look scroed, i should have really inspected it really closely.
 

ihredneck

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  • / SRM-210 Boggs After Running - Fix With Turning Sideways or Opening Tank Cap
SOLVED: Delayed I know.

Thank you JP1961!

It was the pulse port! I pulled the carb and gasket and mated them up and sure enough the gasket had been put on backwords at the shop that had installed the carb, fuel line kit and some other things.
It appears they reused the old gasket and didn't bother to verify it was on correct oh so it wasn't blocking the port.

Anyways, I flipped the gasket (had to trim it slightly to fit) and buttoned it back up and runs great!

Boy spent too much money on it making it run, oh well at least it has all new gaskets, selas, carb, lines and ring.
 

bertsmobile1

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  • / SRM-210 Boggs After Running - Fix With Turning Sideways or Opening Tank Cap
SOLVED: Delayed I know.

Thank you JP1961!

It was the pulse port! I pulled the carb and gasket and mated them up and sure enough the gasket had been put on backwords at the shop that had installed the carb, fuel line kit and some other things.
It appears they reused the old gasket and didn't bother to verify it was on correct oh so it wasn't blocking the port.

Anyways, I flipped the gasket (had to trim it slightly to fit) and buttoned it back up and runs great!

Boy spent too much money on it making it run, oh well at least it has all new gaskets, selas, carb, lines and ring.

Two ring blue smokes are always worth fixing.
 
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