Stihl ms 310 runs on full choke only

[Chuck Spitler]

A friend who thinks I know how to fix things brought me this saw, it belongs to a friend of his. I can get it to start and run in full choke as soon as I take it off choke it dies. I was able to download a Stihl owners manual and it says Low speed needle a 1/4 turn open and High speed 3/4 open does that sound right? seems awfully small opening, especially for the Low Speed. I had the carb apart and I think it is clean..not sure if the pump is pumping enough gas. Not sure it is getting the impulse air that it should. I noticed that when I take the carb off after running it (with the choke on of course) the gas line from the tank seems to be pressurized and it squirts gas. Another question what is the function of the little horn on the top of the carb that the air cleaner fits into? I have not seen this on other makes of saws. I am ordering a carb kit, it is a HD-21c carb and takes a K10-HD kit. Anybody who can give me an idea of what else should I be looking at would be appreciated.

Did I mention that I was told that the owner replaced the 'jar' I think that means the cylinder so maybe I have some air leaks some where?

thanks

Spit

 

[Ozhoo]

Those carb settings are with the limiter tabs installed. Don't run it any more until you do a vacuum/pressure test.

 

[LoveStihlQuality]

Carb kit and fuel lines and filter good too. Take trim limiters at same time. Got my bil's 310 running good. Gor a lot of snort.

Sent from my SM-N900P using Tapatalk

 

[backhoelover]

Carb kit and fuel lines and filter good too. Take trim limiters at same time. Got my bil's 310 running good. Gor a lot of snort.

Sent from my SM-N900P using Tapatalk

second his statement

 

[rattler362]

Third

Sent from my XT1060 using Tapatalk

 

[angelo c]

Pressure test for air leaks.

 

[Ozhoo]

Pressure test for air leaks.

second his statement

 

[backhoelover]

You can get a oem carb for that saw for a few dollars more then a carb kit

 

[SEAM]

Sounds like a cracked fuel line - they bend at a ridiculous angle behind the carb.

 

[Chuck Spitler]

A friend who thinks I know how to fix things brought me this saw, it belongs to a friend of his. I can get it to start and run in full choke as soon as I take it off choke it dies. I was able to download a Stihl owners manual and it says Low speed needle a 1/4 turn open and High speed 3/4 open does that sound right? seems awfully small opening, especially for the Low Speed. I had the carb apart and I think it is clean..not sure if the pump is pumping enough gas. Not sure it is getting the impulse air that it should. I noticed that when I take the carb off after running it (with the choke on of course) the gas line from the tank seems to be pressurized and it squirts gas. Another question what is the function of the little horn on the top of the carb that the air cleaner fits into? I have not seen this on other makes of saws. I am ordering a carb kit, it is a HD-21c carb and takes a K10-HD kit. Anybody who can give me an idea of what else should I be looking at would be appreciated.

Did I mention that I was told that the owner replaced the 'jar' I think that means the cylinder so maybe I have some air leaks some where?

thanks

Spit

thanks for the info. I do not think it is a cracked fuel line, since when I removed the carb a jet of fuell under pressure shot out. I would assume if the line was cracked that pressure would dissipate on its own. There are no limiters on the carb. and the adjustment needles are slotted not tamperproof, What do you suggest as an initial setting for each needle? 1 turn out each? And finally and most importantly, can you walk me through how I should pressure check it. I am not sure how and what I should do. Not sure that I have the right equipment...I do have an air compressor that I can turn the PSI way down on if need be, I have a pressure gauge that screws into the spark plug hole. I also have a gauge for checking fuel pressure on EFI of autos. And I am not opposed to buying a important piece of test equipment either.

Thanks again
Spit

 

[Ozhoo]

1 turn out is always a good start on the H & L jets.

You can always do a redneck vacuum test. Block off the intake and exhaust ports using gorilla tape and attach a rubber hose to the impulse port. Now us humans can pull -5psi of vacuum on a good day, so you become the vacuum pump. Pull a vacuum and hold it, shoot for a minute or so.

The correct way would be to use a mityvac and test both vacuum and pressure while rotating the crank.

But I suspect that it won't even pass the redneck vac test since the owner put that new "jar" on it.

 

[hardpan]

Search "pressure test" and there is a ton of info.

 

[Chuck Spitler]

A friend who thinks I know how to fix things brought me this saw, it belongs to a friend of his. I can get it to start and run in full choke as soon as I take it off choke it dies. I was able to download a Stihl owners manual and it says Low speed needle a 1/4 turn open and High speed 3/4 open does that sound right? seems awfully small opening, especially for the Low Speed. I had the carb apart and I think it is clean..not sure if the pump is pumping enough gas. Not sure it is getting the impulse air that it should. I noticed that when I take the carb off after running it (with the choke on of course) the gas line from the tank seems to be pressurized and it squirts gas. Another question what is the function of the little horn on the top of the carb that the air cleaner fits into? I have not seen this on other makes of saws. I am ordering a carb kit, it is a HD-21c carb and takes a K10-HD kit. Anybody who can give me an idea of what else should I be looking at would be appreciated.

Did I mention that I was told that the owner replaced the 'jar' I think that means the cylinder so maybe I have some air leaks some where?

thanks

Spit

So I am totally convinced that the problem is air leaks, from the jar replacement the owner tried to do...so I am going to open a new thread and ask a few more questions. thanks

 

[heyduke]

Carb kit and fuel lines and filter good too. Take trim limiters at same time. Got my bil's 310 running good. Gor a lot of snort.

Sent from my SM-N900P using Tapatalk

better to replace the carb. carb kits are a gamble. carbs are usually cheap.

 

[67L36Driver]

Pull the pump side cover off the carb and check the inlet screen for trash.

 

[Chuck Spitler]

I actually changed the screen since a new one came in the kit....but it did not have any junk in it.

 

[HarleyT]

I actually changed the screen since a new one came in the kit....but it did not have any junk in it.

The main thing is to look through and clean the passage underneath.


Are the red limiters removed from the adjusters?

 

[backhoelover]

I think there is just one red limited on high side Harley