lack of vacuum

[Spootinay]

I removed the carb and placed the palm of my hand over each carb boot and turned the engine over one at a time. #3 carb boot had noticeably less suction than 1 2 & 4. On one two and four my hand was suctioned on to the boots whereas on number three my hand wasn't suctioned to the boot.

What does this mean? Do I have a hole in the piston or what?

[Stepka]

I had kinda the same problem and it was that the valves were to tight

[jetmechmarty]

Do a compression check. Is the same cylinder low?

[TopCatGr58]

Aside from the valve lash/clearance possiby being too tight, you may also have a vacuum leak in the boot itself, or where it mates to the engine, as well as the SYNCH PORT...that cap can dry, harden, and leak also! As stated, check the compression if you have a gauge, if not, then check your valve clearance...you should have/own a feeler gauge.

T.C.

[Stepka]

Easy way to see if it is a boot or hose, is to spray carb cleaner or starting fluid on the item you suspect.

[cywelchjr]

The carb cleaner trick only works if you have a running engine. If your doing checking before you even try to start it, that trick isn't going to work. That said, as compression check will tell you if it's valves or not real quick thought, cause if the compression is good and the valve clearance is good then it's not valves and you can start looking at the intake track for a leak.

[planedick]

Compression check

Do a compression test dry then again with a little oil in the cylinder. This will tell you if it might be bad or broken rings. A better (higher) reading after the oil will help seal bad rings and make a higher reading if the rings are bad.