stihl ms170 not getting fuel

[IHRed]

brother brought me a ms170 that he picked up somewhere and asked if I would get it running for him. Guy he got it from said it won't start and that's it. compression feels good, piston and cylinder look good through the ports. Fuel system was crap. horrible old gas, carb gunked up, fuel line was really soft and deteriorated. So I rebuilt the carb, new fuel line and filter, spark plug and air filter. Has good spark but pull and pull and no fire. Not getting any gas to the carb. If I pull the top cover and drip a little gas into the top hole of air filter with dropper it will fire on first pull and seems to run good for the few seconds before it runs out of fuel again. Then no more action until I give it some more gas. Little research shows the pulse line is kinda built into the boot??? Is this where I should be looking? give me some direction if not. Only thing on the system I haven't replaced/renewed so that is my suspect but this is my first rodeo with a 170.

Thanks guys


Joe

 

[Stihl working hard]

Is the tank vent blocked

 

[IHRed]

Is the tank vent blocked

need to check and be sure. wouldn't it still start just not stay running long once tank builds vacuum??

Thanks

 

[Thommo]

The impulse is part of the intake boot and can be kinked over on the cylinder end if not put on correctly. I would try spraying something like WD40 through all the carb passages to make sure they are not blocked too

 

[HarleyT]

Go through the carb again, if no luck. Go to the Stihl dealer and get a new carb for @ $21..

 

[s sidewall]

Make sure you got the boot on correctly, if you took it off.

Steve

 

[IHRed]

OK guys will check some of this stuff out tonight. I did not have the boot off but should have checked it out. when I pulled the carb off for the first time there was what looked like some pieces of grass smashed between the carb and boot so obviously someone has been into it at some point.

Thanks


Joe

 

[HarleyT]

Generally, Hoosiers are the only ones that have trouble putting their boots on......

 

[IHRed]

Ok got a chance to mess with it for a while. first thing I did was check the tank vent, it's good. Then I decided to eliminate the carb as the issue so I took it off and put it on another nearly brand new ms170 that I have here. That saw started and ran fine with my rebuilt carb on it so that's not the problem. When I put the rebuilt carb back on it's original saw it started right up and ran for a short period of time then slowly bogged down and died. Now I can get it to start and idle for a short period of time but only with the switch in just the run position. If I choke it at all it will not even fire at all. switch it back to run position and it will start and idle for a bit then stall out and die. When it is idling any throttle at all will bog it down and kill it. ideas???

Thanks

Joe

 

[HarleyT]

Aftermarket fuel line? Pull the muffler and look at the piston. Pull the boot off and make sure that it is on correctly.

 

[HarleyT]

Here is a boot that I pulled off one once.

 

[IHRed]

OEM fuel line(green). piston and cylinder look good through exhaust and intake ports. Only thing I have not had apart on this thing(other than the engine itself) is the intake boot. That's coming apart tonight. Will let you know what I find.

Thanks


Joe

 

[Wicked500R]

That boot is your problem. The impulse port was smooshed closed and not in the port. And that boot is deformed pretty bad. Here is a boot off a 180,

Just noticed Harley posted that bad boot. This is what it should look like,

 

[Wicked500R]

You'll need to pull the engine to get that boot out.

 

[IHRed]

Impulse line of the boot was partially pinched off. got it reassembled correctly and the saw starts and runs like a champ now.

Thanks guys


Joe

 

[HarleyT]

Great, glad you got her going.

 

[HarleyT]

Here is a real "Bad" boot...........

 

[HarleyT]

You really need to pull to get that boot out!!!

 

[Chashowlett]

It's Christmas time. You could make a lamp out of that boot