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75 hp Mariner 4 cyl.

Neither new or older Merc triples will go--wrong driveshaft splines and other problems.

There's PHs for your motor on E-Bay for under 400 bucks regularly.


Jeff
 
I kinda agree with you faztbullet, seems like a big gamble. After all, the motor I have now was supposedly a good one according to the previous owner. I don't really like the idea of spending a couple of grand on a re-manufactured powerhead because like I said before there are still going to be a lot of old parts on there...parts that are getting harder to find. I'm thinking I might just find another engine and either trade mine in or sell it as is. There are lots of good parts on it and it runs great above idle. I might even just keep using it until I find another one. My preference would be to get a later model Mercury 75 hp. I've never owned anything other than Mercury or Mariner, so I'm less familiar with the other brands but I would consider anything. I'd really like to get into a 75 Optimax, both of my other Optis were great. Guess I'll start frequenting eBay and Craigslist to see what I can find.
 
I guess you're right...now thinking there might be more wrong on #3 then. I've had valves get messed up on 4 cycle engines that could have varying effects on compression, but thinking about it now the reeds are completely below the piston on the compression stroke. Hopefully I can find a repair/replacement option soon. I hate using something when I know there I something wrong with it.
 
Life is a gamble! You always take a chance on buying objects off E-bay, but a few hundred bucks from a reputable seller (check his rating) is a good bet rather than dropping a grand on a rebuilt PH for a motor only worth 500 bucks if it's running.

Jeff
 
Life is a gamble! You always take a chance on buying objects off E-bay, but a few hundred bucks from a reputable seller (check his rating) is a good bet rather than dropping a grand on a rebuilt PH for a motor only worth 500 bucks if it's running.

Jeff

That's my hang up with this whole deal. The motor isn't worth much in running condition, even less now. There are good parts on it, but I'm not going to part it out. I priced a new 60 hp Mercury 4 stroke a little while ago...Came in around $9k (worst case, could be up to $1000 less). That want really attractive either. Looks like no matter what I do I'll end up with something used and hoping for the best.
 
I've looked around the web and can't really find any 4 cylinder powerheads like mine for sale. I've searched Craigslist for any used engines as far as 300 miles away and no real leads there either. I contacted a couple of rebuilders (online, not local) and wasn't really encouraged by them either...one even told me to not repair mine! At any rate, they were each about $2000 after shipping and such. I've searched eBay, tons of 3 cylinder no 4 cylinder. The mechanic that found the damage won't repair it. He referred me to a local Yamaha dealer who gave me a price of about $7500 for a new F70LA engine with new controls and rigging. As bad as I hate to spend that much money it might be my best path forward. I've also considered selling the whole rig as is, but not sure how well that will go with a wonky motor. I'm thinking of adjusting the idle speed to about 1200 rpms and see if its better. That is the RPM where it seems to idle best, but that is with the throttle partially advanced. I know that will be hard on the lower unit, but at this point I don't really have much to lose. Maybe it would be good enough to get me through this season.
 
Ebay item # 182325390547

Guy wants WAY too much for it, but it's been for sale a looooong time, so...


I'd offer him 300 bucks and work upward from there.

Jeff
 
Ebay item # 182325390547

Guy wants WAY too much for it, but it's been for sale a looooong time, so...


I'd offer him 300 bucks and work upward from there.

Jeff

I saw that...wasn't sure it would work for me since it came off an 81 model. I'll check it out further, thanks!
 
There's two basic "Big Four" type motors; the distributor model, and the ADI (non-distributor) model. This particular one is the ADI type. I believe that's what you have, right?+

Jeff
 
Yeah, mine is the ADI type. What all will I need for a swap? Never done one before. I'm sure there are some gaskets and such I'd need.
 
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