Small Engines (Lawn Mowers, etc.): 2 CYCLE PROBLEM, engine bolts, vent valve

Question
QUESTION: Good day....I have a Ryobi 2 cycle hand held blower model 280R with a Walbro WT-827-1 carb...the complaint was it would start, run for a minute or so, then the engine would cut off....due to the age of the unit I performed the following repairs: Replaced the carburetor, all fuel lines, primer bulb, and the in tank fuel strainer....I also flushed the fuel tank, checked the muffler/cylinder for blockage, tightened all engine bolts and screws, and checked the gas cap vent valve for proper operation....the engine will start up, run for a few minutes, then start to die....pushing the primer bulb or sliding the choke half closed brings it back to life....it is in my opinion I have a lean condition going on....am I missing something??....thank you in advance for any help you can provide...Mark

ANSWER: Have you checked the engine compression?  Most engine loose some compression when they are warm.  

What is the engine compression cold and when it stops running?

Eric

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QUESTION: Good morning....compression is good cold and hot....I did not put a gauge on it but I have resistance even when the engine is hot....plus...when the engine starts to fade out all I have to do is slightly push the primer bulb or move the choke lever partially closed and it keeps running...carburetor was installed right out of the box....no adjustments made at all....I don't think richen it up would help my problem....would making the mixture richer compensate for a compression problem?

Answer
No, a richer will not compensate for low compression.  I have had similar issues as you described and it ended up being a compression problem...that's why I always check compression second...spark is first.

It does sound like you might still have a carb issue but you can only rule out comopression if you have at least 110 psi on a cold engine.  I have had Ryobi start on 70 psi but the blower had no power and would not idle.   Could not re-start once it the engine was hot.

You could pull the carb apart and check the inlet arm to make sure it is the correct height and make sure the diaphrams are not stiff and brittle.  I once had a brand new carb with the metering arm set too high.  It took me, and a couple of other techs a long time to fix it...I finaly noticed the issue but none of us thought the carb was the issue.

Did you download the Walbro service manual which had the meter arm setting procedures?

Eric