What year did merc start HP ratings at the prop

[boatnut74]

Tonight I'm going to look at a 90hp merc for my starcraft. He says he thinks it's early 90s but said he doesnt know for sure and doesnt have any pics. I did some research and came up with a dozen different answers. They ranged from 81 to 89. One I saw said when the switched from distributor ignition to coil ignition is when they started rating them at the prop. I'm just looking for a little clarification on this.

 

[emckelvy]

Re: What year did merc start HP ratings at the prop

'82-'83 was the transition year.

If the 90hp is a 6-cylinder, it can't be a 90's-vintage motor since the last year of production for an Inline Six was 1988.

A 90's-vintage 90hp would be a 3-cylinder model.

In any case, the serial # will tell all.

BTW the switch from CDI-distributor to ADI had nothing to do with HP ratings, and started in the 70's with smaller-hp motors. The last Inline Six distributor models were produced in 1979.

HTH..........ed

 

[boatnut74]

Re: What year did merc start HP ratings at the prop

Thanks for the info. Is there any information in the model number or serial number that states the year? I know the johnnyrudes did but im not sure on the mercs.

 

[emckelvy]

Re: What year did merc start HP ratings at the prop

Here's a couple I use quite often:

Mastertech Marine -- Mercury Outboard Motor Model Year Reference Chart THRU 1996

Mercury identifikation, fastst?ll modell utifr?n serienummer, modellkod

 

[boatnut74]

Re: What year did merc start HP ratings at the prop

I talked to him again and he says he thinks its an inline 6. He said he thinks the boat is an 89. Im thinking they should be about the same year but im not sure when they quit producing the 90hp I6's

 

[boatnut74]

Re: What year did merc start HP ratings at the prop

I looked back at your first post and 88 was the last year. I guess I need to re read sometimes

 

[boatnut74]

Re: What year did merc start HP ratings at the prop

Turns out the boat is a 77 and the motor is of the same vintage. He wasnt really sure what he had. I'm still going to pick it up since it comes with a spare 115 parts motor.

Thanks for all the help and information.