Re: Advance timing specs on a Mercruiser 470
Wow, thanks for the info. This is just what I've been looking for. The quick reply to my first post tells me I should have asked for help sooner! Background: I bought a 21' Glasply a couple of months ago. It was supposed to be turn-key, but a lot of bad things seemed to happened to it while towing it home :| I've learned my lesson and will insist on a test drive before buying again - no matter how honest and straight the seller appears to be. After replacing the stern drive water pump plus a list of other things, I still can't get the engine to run properly. The engine has been recently rebuilt and I suspect has never run right. At about 1500 RPMs the engine begins to miss and run very rough. I checked the initial timing and found it to be at 12 degrees BTDC. I adjusted to about 4 and it ran a little better but still with the same basic symtoms. While running at about 2000 to 3000 RPMs, I played around with the distributor and found a setting where the motor seemed to run smooth and quiet at higher revs, but would not run at lower revs. I checked the centrifugal advance mechanism and it appears to be working fine. Bottom line is I can set timing so the engine runs well at low RPMs or at high RPMs, but not both. I have a couple of thoughts: Something is wrong with the distributor causing it to advance the spark too soon or too far or is it possible that the valve timing was set incorrectly upon reassembly? Note: to make the engine run smooth at higher RPMs, I have to turn the distributor clockwise to retard the spark. Thanks so much for any thoughts or advice.
: http://www.4shared.com/document/M35B2RL4/Service_Manual_03.html
