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macaw
09-20-2012, 09:04 AM
Just picked up an old merc 4 cyl and still not sure exactly what it is. The serial number looks like it has been intensionaly scaped off at one time. The red decals would put it at 1970 - 1971 800 merc but under the hood in front of the carbs the sticker says: timing .172 BTDC 27* .Acording to My manuals the merc 4cyl were 23* BTDC untill 1973. The power head looks new under the hood and has no paint just the original bright aluminum. It apears to have the type III thunderbolt pointless CD ignition, 2 side bowl carbs, spark at all plugs, and has between 145 and 150 lbs compression on all 4 cylinders. The lower unit seems to shift properly and was full of dirty grease but no water, shavings, chips, or grit. I have not tried to start it. I found it on craigslist for $50 and thought that if it was properly restored it would make A great motor to put on the back of My Checkmate Playmate GT. By the time I would get finished with A rebuild and all the powder coating I would want to do before running it I would have around $2500 in it but it should be A nice dependable and fast setup but I would like to know for sure what it is before I start ordering parts.

Popa Sam
09-20-2012, 05:09 PM
If my old memory is close, it would be between 1969 and 1971. The timing decal is correct for that motor. If you can post a few pictures.

macaw
09-22-2012, 05:43 PM
Sorry I have not been back on but I am working 16 hour days right now. After bringing the tag in under the magnifier and cleaning it up some more it does show as A 1970. I guess that My manual is just wrong on the timing. I am hoping that after A complete rebuild it is A good dependable motor. I have not ran one with A distributor since My first boat and 1957 60hp and that was over 30 years ago.

If my old memory is close, it would be between 1969 and 1971. The timing decal is correct for that motor. If you can post a few pictures.

Popa Sam
09-23-2012, 09:12 AM
The timing shown in your manual is probably taking today's so called gas into consideration.