Mercury Mark 30 Timing

[Mike444z]

I have a Mark 30 and the timing belt broke. Now im trying to get the motor back into time there are 2 timing marks on the flywheel one is at TDC the other is 0.235" before TDC, which one do i line up with the magneto timing mark? Thanks

 

[emckelvy]

Re: Mercury Mark 30 Timing

Line up the arrow on the dist pulley with the TDC mark. The other mark is for setting maximum timing advance. You'll need the special Mercury tool or a compatible dial indicator to make that adjustment.

Here's some info that should help clarify:

http://www.maxrules.com/oldmercs/timing/20.pdf

This and more accessed from this very helpful reference library at the Maxrules site:

http://www.maxrules.com/timingindex.html

Those Mk 30's are a sweet runners. I have fond memories of a MK30E that I fixed up in the 80's. Wish I still had it!

HTH...........ed

 

[ArcadianStar]

Re: Mercury Mark 30 Timing

I spent a life time racing Mark 30-H's and Mark 55-H's. Make sure the little arrow on the mag's "GEAR" points to the arrow on the flywheel. Hell...I think ZERO. Then, assuming the mag IS RIGHT...

Sorry, I'm not helping here...You'll need a dial indicator, we used to run about .400 to .500 advance with HO-3 Champions...But normal use should be about maybe .300 with probably L77 JC -4 Champions.

I'm going to suggest going to www.boatracingfacts.com for more info...Just go to the technical thread, someone there will know for sure.

ADD:

Odds are if the belt broke, the mag arm is broken and dropped down. We used to fix these two ways:

One, we took the mag arm apart, machinged agroove in the arm , then threaded a 1/4 boldt in to hold it.
Two, we used o-rings around the mag vents to a 1/4 20 bolt above the mag to support the mag arm.

I never broke a belt without having a broken mag arm. The early ones had brass 'TITS" holding the arm, the later ones were steel. The brass ones all broke, the steel ones could be hammered tight and they never broke....

A quick check for shaving under the pulley will tell you if the mag arm dropped down.

Good luck with you Mark 30. I still have a Mark 30-H.

 

[Mike444z]

Re: Mercury Mark 30 Timing

Ok thanks for the help.

 

[Mike444z]

Re: Mercury Mark 30 Timing

Do you have any idea where to get a dial indicator?

 

[ArcadianStar]

Re: Mercury Mark 30 Timing

Go to www.boatracingfacts.com and ask your question. You MAY not need a dial indicator.

This has been bugging me, but I think you just point the arrow on the mag gear to top dead center and you will be fine.

Things that were once EASY, AREN'T...