Mercury 140 straight 6 tower of power

[Nufhead]

I have just picked up a mercury 140 straight 6 tower of power. Just need some tips for a prop size. 600 kg 18 foot fiberglass boat. I have the cerial number but cant seem to find any info on it. mercury serial number: 8003060 the old prop number is :84-77348-21 and cant get a match on it either. It is a vintage 1970-1980. Got any tips?

 

[Faztbullet]

If the motor runs a 17pitch is close to what you want....

 

[Chris1956]

The Maxrules web site will help you get a year on it. It is likely 1978-1980. A motor of that year will have six ign coils.

Since the cowls interchange easily, the serial number can also verify HP. An IL6 can be rated from 90HP thru 150HP, and be virtually identical.

 

[Scott Danforth]

your old prop is a 21 pitch which may have been on a lighter boat.

first, I would mount the motor, make sure its running ok, then get RPM and GPS speed to dial in a prop for your boat.

 

[jimmbo]

The Maxrules web site will help you get a year on it. It is likely 1978-1980. A motor of that year will have six ign coils.

Since the cowls interchange easily, the serial number can also verify HP. An IL6 can be rated from 90HP thru 150HP, and be virtually identical.

A 78 would have a distributor and one coil, 79 was the first year of the ADI, with the 6 coils. There also a chance it is a 1972. A completely different powerhead, it too would have a distributor. 1981 was the last year for the 140

I was going to ask if the cowl says 140, or 1400? but as mentioned cowls can be swapped. Post a pic, we can probably identify the year of the cowl.

 

[Texasmark]

If the motor runs a 17pitch is close to what you want....

+1.....gets my vote. If he doesn't know who does???????? Notice the black thing in his Avatar and the Hydra-Sport in his lineup. The first time I saw a Hydra-Sport was back in the mid '70's era. Was quietly fishing in a quiet cove while hearing this high pitched singing noise. Looked up and two boats were in visual contact. One was passing to the left and the other approaching from the left. The latter was blue and had this black spot at the stern protruding above the outline of the boat. As it got abreast of me, it met the shallow wake of the other boat and immediately it went airborne where I could see daylight under the entire boat....only thing in the water was the lower unit and part of the spinning prop.

As It went by, in awe and amazement I saw the name and the blue band hp of a 150 Tower. Very impressive.

 

[Nufhead]

Thanks guys. It runs smooth. The 17" feals good

 

[merc850]

Install a tach to keep an eye on performance and whether you're running in the max. rpm range.