1979 mercury thunderbolt (pressure)

[paul tracy]

was wondering if anyone can tell me what my max pressure should be on my motor and also does it mater on the gas and oil you use , should it be top of the line. i kinda think that why i melted a ring

 

[Moody Blue]

Re: 1979 mercury thunderbolt (pressure)

Lots of motors made in 1979. Which model do you have?

What pressure are you asking about? Compression?

As for gas and oil, nothing special required. Regular 87 octane gas and any marine 2 stroke motor oil mixed in the proper ratio will be fine for your motor.

 

[paul tracy]

Re: 1979 mercury thunderbolt (pressure)

yes i was refering to compression what is the max it should be 140?

 

[Moody Blue]

Re: 1979 mercury thunderbolt (pressure)

Won't find a max spec on compression anywhere. There are alot of factors that determine the reading and that makes it hard to assign a number.

Most manuals won't even give a typical spec. More important is the uniformity between cylinders. A motor will run well at low compression if all cyls are the same, but the same motor with some cyls at higher and some at lower compression will run like crap.

Generally accepted rule is that all cyls should be within 10% of each other.