Mercruiser 488 Timing issue

[truckermatt]

I didnt really want to start this thread because there are many others out there asking the same thing... But i haven't been able to use there info to help me yet.

My Merc 488 (which is the 4 barrel version of the 470 motor) needed a new Distributor and i replaced it, but now i dont know how to set the timing back out correctly to get it to start.

I tried lining up the lines on the fly wheel with the ZERO mark, and then seeing when the distributor points and then put the cap over the with the #1 by it... but that hasn't worked yet. I have tried it several time in different locations.

I have the mercury manual also.

Thanks
Matt

 

[Euro95]

Re: Mercruiser 488 Timing issue

You could be 180 degrees off with your way of doing it. Don't you guys tell to pull the plug of #1 to feel when it's on the compression stroke?

 

[truckermatt]

Re: Mercruiser 488 Timing issue

You could be 180 degrees off with your way of doing it. Don't you guys tell to pull the plug of #1 to feel when it's on the compression stroke?

If i pulled the #1 plug... what would i try to feel for ?

 

[markNitram]

Re: Mercruiser 488 Timing issue

With the # 1 plug removed, take a "plastic drinking straw" place in spark plug hole, bump your starter over and watch the straw to bottom out then top out, and there you go. DO NOT use anything metal to prefrom this !!

 

[ziggy]

Re: Mercruiser 488 Timing issue

If i pulled the #1 plug... what would i try to feel for ?

compression.

with plugs removed, put your finger over the #1 plug hole and feel for air trying to blow your finger off the spark plug hole. this indicates the piston is coming up and creating compression because the valves are closed. once coming up on the compression stroke, then ya can line up your timing marks and be at tdc of the compression stroke. when installing the distributor, point have the rotor pointing to #1. when i've done it. i usually remove all plugs and turn the engine over by hand. your only wanting to feel the compression building indicating your on the compression stroke.

then set dwell (adjusting the points) with a dwell meter. then set timing with your timing light. set dwell 1st, then timing. dwell effects timing. timing does not effect dwell.

 

[JustJason]

Re: Mercruiser 488 Timing issue

pull all the plugs, safely ground the ignition system. Then bump the starter over with a remote start button. Lick your finger and put it on the number 1 plug hole. You want to feel COMPRESSION building up against your finger. after you feel compression use a screwdriver and then rotate the engine by hand until the piston is at TDC.

 

[Don S]

Re: Mercruiser 488 Timing issue

May 10th, 2009, 09:12 AM

I would hope the guy has it timed by now.

Welcome to iboats markNitram, please don't reply to old post.