Max spark advance 75 horse Mariner

[starkyb]

Can anybody tell me the max spark advance on a 1988 75 horse 3 cylinder Mariner. The manual I have says 2 different things in 2 different parts of the book. When I set the timing, do I set it at less than what the manual says or right at the number?

 

[Bondo]

Can anybody tell me the max spark advance on a 1988 75 horse 3 cylinder Mariner. The manual I have says 2 different things in 2 different parts of the book. When I set the timing, do I set it at less than what the manual says or right at the number?

Ayuh,.... Which manual,..?? What differences does it state,..??

 

[starkyb]

The forum won't let me reply

 

[starkyb]

My Seloc manual says 18 degrees max spark in chapter 7 and 30 degrees in the back at WOT. the motor says 24 degrees @ 3000 rpm

 

[oldman570]

The Seloc manual can make it hard to understand some things at times. As for setting the timing on the motor, the 30 degrees at WOT is when the motor is at or near 5300 RPM and needs to be done in a test tank with a test wheel in place of the prop[. The 24 degrees has to be done when the motor is in a test tank also. The 18 is with the motor at idle with the motor in FWD and in water. On most motors the timing advances as the RPM increases and it is best to check the timing at the idle and the WOT to make sure that the motor is where it should be and not firing the cylinders before those settings. I usually set my motor 1 degree less than what is called for to be sure that the motor dose not predetenate and could cause damage to the motor. JMO
Oldman570

 

[starkyb]

The year before Last I set it at 28 degrees with the plugs out and cranking it with the throttle arm against the stop. It's been running fine but I didn't know if damage was being done from a bad setting that just hasn't shown up yet. The motor runs great.

 

[1nebel0]

Less advance given our bad quality of gas is always better....Too much timing and you will blow a hole through a piston....Leak Down test will tell you overall cylinder condition.. much more accurate than just a compression test..Don't buy a Harbor Feight testor...JUNK