help mac sp81

[DAN666981]

need help with a mac sp81 that will not restart after its been run. carb has been re done its driving me just bat crap carzy.

 

[fossil]

Check you fuel cap vent. They often turn to goo. Crack the cap open when it won't start and see if that helps.

 

[2broke2ride]

This is a common problem with McCulloch saws. I have a 10-10 that was doing the same thing, a new fuel cap fixed it. It still starts hard hot (3-4 pulls) but it starts which is better than before. The tank vent has to let air in as well as letting a little pressure build in the tank or the fuel will boil causing vapor lock. At least that's my take on it.

 

[DAN666981]

ok fossil I now it leaks fuel out the tank vent when its on its side. and 2broke2ride the local saw shop is tring to help me with parts but there getting harder to come by.

 

[fossil]

ok fossil I now it leaks fuel out the tank vent when its on its side. and 2broke2ride the local saw shop is tring to help me with parts but there getting harder to come by.

Post a pic of the bottom of the cap. There are different types of vents. Many can be easily taken apart and a new duckbill valve put in. I've done it on a couple of Mac caps. Works well.

Mark Heimann did an excellent write up on them but I think the pics got lost in the AS Fubar a couple of years ago

 

[2broke2ride]

ok fossil I now it leaks fuel out the tank vent when its on its side. and 2broke2ride the local saw shop is tring to help me with parts but there getting harder to come by.

Ya, I know. I paid through the the nose for an nos cap on eBay for the 10-10. Parts for these older macs can be tough. Did you check chainsawr.com?

 

[DAN666981]

the bottom of the cap has a metal tub like vent in it.

 

[DAN666981]

no I haven't 2boke but I think the saw shop mite have one he was looking for me.

 

[Chainsaw Jim]

Most just yank those stupid vents out and run em without one. They shouldn't leak on their side if they're running.
You can drill the hole large enough to jam a fuel line in it for either a Stihl or echo vent. But it sticks up like a little pig tail.

 

[DAN666981]

ok jim I will see what I can do with the cap.