1050 cold start prolem

[buzz sawyer]

Got a puzzler here. My Homie 1050 with a Tilly HL doesn't draw fuel from the tank after setting for a few weeks. I can prime the carb a few times and it fires up each time. Then after 3-4 times, I see a surge of fuel coming through the line from the tank. Starts on one pull after that and runs great. Compression is 170. All the crankcase pulse passages are clean. Seemed like a sticking needle but it doesn't appear to be sticking. Diaphragm and carb gaskets are new. I've raised the needle tang a little - no change. I've swapped the position of the diaphram and gasket thinking it might need less travel - no change.

Spark is fine when it doesn't start. Once the fuel flows, I can start on 2-3 pulls cold, one pull hot. I have not replaced the needle or seat but that may be my next try. Also thought the needle spring could be too tight.

I'd sure appreciate any input on this one.

 

[PES+]

I have seen the same thing

The new gas formulation seems to like to make the fuel pump flaps stick to the carb body until you pull enough to get them to un-stick.

It is time for the diaphram material to be changed again.

The black type that are available do not like the ethanol blends too much

 

[PES+]

You can try what I always did in the 80s

when you get done with the saw pull the fuel line from the carb and plug it with a golf tee.

Then run the saw out of the fuel in the carb and spray WD-40 into the inlet nipple unitl it does not take any more......then just reinstall the fuel line

 

[GPH85]

Just a thought here, but is the fuel line OK? I was running into this problem using cheapo clear type fuel line which was allowing air into the line through the pressuring and depressuring durring the heat cycling after the saws were cut off. Now I use good thick and tight sealing 3/16 high grade actual fuel line. Saws usually take 6 pulls absolute tops even after sitting for a couple months. Another thought --- is the breather in the fuel cap allowing the tank to breathe, causing suction in the tank after it's cut off? I know it's a long shot, but still a possibility... Then there's the rebuild...

Just some thoughts on the subject...

 

[buzz sawyer]

Thanks - greatly appreciate the ideas! I will check the vent on the cap - hadn't thought about it. It's a long way up from the filter to the carb on this thing and any restriction would slow it down.

Interesting about the fuel line - it is the transparent yellow line I get from my local repair guy - as long as I can see fuel in it, it will start - whether is sits for a day or a week. No visible fuel, no start. Sticking flaps make sense but the pump diaphragm is new synthetic material. I think the only think I have not replaced is the needle and seat.

I'll try your suggestions and report back - Thanks again!