Mercury Mark 30 Timing

[Mike444z]

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

[david bryan]

0235 would be the stock timing but more is better i ran my 30 h at 375 thousand be for top dead center

[Fastjeff57]

The arrow on the distributor (below the top plate that comes off) should point at the mark to the right (as you stand in front).

Jeff

[Phil McDaniel]

Take #1 cyl. to TDC,move arrow on pully to center of crank, put belt on. It's done. Motor will be in time. Has nothing to do with the timing before TDC as to when you want your cyl. to fire. Phil

[Mike444z]

Thanks for all the help. If i wanted to advance the timing to something around 0.375" before TDC is there a special dial indicator i would need?

[Fastjeff57]

Timing requires a timing tool, or you can degree the flywheel and use a timing light. That's about 38 degrees of advance, by the way, which is a LOT with today's crappy gas. I'd stick with the stock timing if I were you.

Jeff

[Mike444z]

Ok i'll just set it back to stock timing.

[Phil McDaniel]

Mike, The last post was to put your motor IN TIME so as when mag fires it goes where it is suppose to, #1, #2, etc.

Now that we have the motor in time let's move the mag. to get the correct timing BTC. With a dial indicator in #1 cyl. find TDC and rotate crank counterclockwise to position in thousands to where you want motor to fire .325,.350, etc.. With a buzz box,flash light timing light, OHM meter(condenser has to be disconnected) you can advance your mag. until buzz box/timing lite lets you know the desired timing has been achieved. Lock down or set stop for full max. Now your motor is in time and timing is set for desired BTDC.

[Phil McDaniel]

Forgot to post; there are other factors which WILL influence your desired timing.
Points that slip and/or a loose belt will cause a variance (will be negative). Front half/crank case cover bolt holes not slotted. Plastic(gray or black) points are no good. The old phenolic are the best. Hope these pointers help. Phil

[Ron Hill]

I never broke a belt that the mag arm had not dropped dow first....I'm sure all the Mark 30's had the brass hangers, not steel.

What do you think??

Talking gas! IS there any good gas? What do outboard racer's use??

[formeone]

renegade 110 oc,,,7.00$ a gal...eek.... airport wont sell to us in a 5 gal gas can here,,,

[Mark75H]

renegade 110 oc,,,7.00$ a gal...eek.... airport wont sell to us in a 5 gal gas can here,,,


Just drive to the next one

[formeone]

hehehehe spokane isint that big.... besides have 175 cranking comp.. figure more octane better,,,,??

[Mark75H]

You are right, there are only 5 airports within 30 miles of you to choose from:

http://www.100ll.com/shownearbyfuel.php?HashID=2762827cc2bbd56a1b450b75 22b845cd

http://www.100ll.com/showfbo.php?HashID=2762827cc2bbd56a1b450b7522b845c d

175 with a good squish band my not require 100 ... you might be able to get away with some good stuff in the mid 90's

My motors crank 275, but they are crappy old deflectors with smaller carbs and more restrictive reeds

[Mike444z]

ok thanks for all the help.

[MikeMcHaney]

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

For posterity - there are two marks on the flywheel, the manual talks about both and is a little ambiguous on which to time to. The mark stamped with the 'O' on it is .235 before TDC, the other plain slash mark is TDC. Point the tiny arrow under the top cap of the magneto (it's cast on the top of a spline) at the 'O' mark, wrap that timing belt on and you are off to the races. Maybe literaly.

[DeanFHobart]

Talking gas! IS there any good gas? What do outboard racer's use??

VP makes various formulas of racing gas, with lead, without lead, with or without ethanol and various octanes. Call VP and find your nearest dealer….. all of them should be on their web site. Check it out.