Newbie

[Vaso]

Hello from Missouri. I'm 60 years old and I just cut firewood for personal use, however love tinkering on chainsaws and have started kinda collecting saws. I have ms170,180.024wb, 024 super, 025, ms250, 026, ms261 (primary saw), 028 super (which I'm having trouble with), ms290. Built the 170 and 180 from parts and rebuilt the 250, several carb rebuilds.

Now my problem! 028av super. Replaced seals, no vacuum/pressure leak. Compression 140. Has good spark. Rebuilt carb. New fuel line/filter. H/L set to 1¼ out. Haven't changed impulse or boot. Getting fuel. Won't start, if does won't idle. ???

 

[cookies]

140psi is low for a rebuild, always replace the impulse if disturbed. Low compression and a leaky impulse will both cause your symptoms.

 

[barfer]

welcome!

Fire triangle… fuel, air, spark.

If you’ve got good spark and fuel… then it’s air

Maybe re-check your carb and choke while you’re replacing the impuse?

Good luck chasing down the gremlin!

 

[Mad Professor]

Did you rebuild P/C or just do seals? If just seals how does P/C look through ex port?

Try a squirt of mix in the carb. If it fires recheck your carb rebuild. Make sure gaskets/diaphragms are same as originals (kits may service several similar carbs) and in correct order. Look over metering needle/ seat.
The plastic fuel line elbows on those carbs come loose too, but that acted like an air leak in my case.

 

[Okie]

Before blaming low compression make sure that your gauge reads correctly when testing LOW CC CHAINSAW ENGINES.

I've repaired chainsaws that others had overhauled due to their compression gauge reading low and the saws compression was actually ok. They would usually say, the compression is lower after I installed new stuff.

Install a NEW correct type spark plug FIRST.

The 028's are one of my favorite saws. The 025's not so much.

 

[Vaso]

Again TY for the advise. The 028 super is up and going. Haven't put it in wood yet, maybe this weekend. All I can say is that WT-16b is a touchy carb.