Partner 370 Won't Start - Help Needed!

[_Chris]

Hi - Here's what I've tried so far:

 

Checked for spark - OK

Used freshly made up fuel

Replaced fuel filter in fuel tank

Cleaned carb - removed some grassy looking stuff from filter in the carb. I thought that this was going to solve it but there is no sign of life at all when I pull the cord. Funny thing is it was working OK earlier in the year.

 

I can see the fuel being pulled through the line when I prime it. Is there any way I can test the carb further?

 

Many thanks

 

Chris

[spudulike]

For a working saw you need spark (with the right timing), Fuel (fuel/air at the right amount) and compression. Is the plug wet once you have pulled the saw over with full choke 10-15 times? Have you checked the compression or at least, taken the exhaust off and looked at the front of the piston and inspected for scoring?

You can try holding the throttle fully open with the right hand and pull over hard with the left....not in the rule book but can help small saws struggle in to life if a bit wet with fuel!

[daveatdave]

have you tried a new plug as sometimes you get a spark when checking but when under compression dos not work 

[Khriss]

......did you loan it to someone ........ K

[felixthelogchopper]

13 minutes ago, Khriss said:

......did you loan it to someone ........ K

Often a good starting point in diagnostics of any kind.

Edited September 30, 2017 by felixthelogchopper

[bmp01]

12 hours ago, daveatdave said:

have you tried a new plug as sometimes you get a spark when checking but when under compression dos not work 

+ 1

Never had a defective plug ..... until the first time and now my default is new plug every time. It was visually fine,   would show a spark just like normal outside of the engine but swapping back and forth between new and old plug proved beyond doubt the old one was knackered. When i cut it up it turned out the ceramic was cracked and it had been arcing inside the plug. 

Rare case but it does happen. 

[_Chris]

Thanks all for the advice.

 

The plug looks dry Spud after I  pulled the saw over with full choke 10-15 times &  the side of the piston isn't scored.

 

I haven't tried swapping the spark plug for a new one yet & I haven't loaned the chainsaw to anyone.

 

I suspect that there is still a blockage somewhere in the carburetor. If I were to remove the high speed and low speed mixture screws and pull the chainsaw over should I expect to see fuel coming out of the holes? 

[bmp01]

50 minutes ago, _Chris said:

I suspect that there is still a blockage somewhere in the carburetor. If I were to remove the high speed and low speed mixture screws and pull the chainsaw over should I expect to see fuel coming out of the holes? 

Nope .... but if you are lucky you might avoid getting some of the surrounding crap down the holes   If you're unlucky things are going to take a turn for the worse 

 

You could wind the screws in gently,  then back out 1 turn each (typical factory setting) but don't hold out too much hope. ...  Most likely the carbs going to need a going through,  inspect and clean plus maybe new gaskets. You should also check the rest of the fuel hoses, filter etc. Thing is,  if you can't get fuel to the saw with the choke on, then some thing is blocked or stuck - your not reliant on the pumping side of the carb under this mode of operation.

 

bmp01

[_Chris]

Doh! - I new it was a silly idea as soon as I posted.

 

I'll dismantle the carb again and re-inspect and re-clean.

 

Cheers

[bmp01]

1 hour ago, _Chris said:

Doh! - I new it was a silly idea as soon as I posted.

 

I'll dismantle the carb again and re-inspect and re-clean.

 

Cheers

I should have paid better attention to your original post. .. so it's been apart already . Two questions, 

1) Are you seeing fuel in the primer bulb?  If so,  that should have filled the metering chamber with fuel.... and it should then at least cough on 2-3 pulls. If no fuel in the primer bulb then, did you get the fuel lines swapped over? Or the filter is completely blocked or the metering valve isn't opening (metering gasket upside down? Check metering lever setting).

2) Is the choke mechanism operating as it should? You need it to create the vacuum to suck the fuel in. ..

 

If you do take the carb apart again,  confirm all jets etc are unblocked with something like WD40 spray through one of those thin tubes.  DON'T use compressed air at full pressure that will knacker the one way valves (one in each of the low and high speed circuits). I've got a short length of silicon hose which is very soft and can be pressed onto the entry to the drillings and sealed by hand pressure - blowing (and sucking) confirms drillings are clear and one way valves are working .... (or not). Doesn't taste the best but you learn a lot 

 

At some stage it might be worth popping some fuel down the spark plug hole, just to confirm the engine will run once the fueling is sorted....

 

Let us know how you get on. 

 

bmp01

 

 

 

 

-