115 tower of power

[digger1?]

my 115 hp mercury outboard in line 6cyl blew out the #3 cylinder and needs to be rebuilt the motor had a piece of piston in cyl which I was able to remove with tweezer I rotated the motor by hand and was able to rotate with no seizure my questionis I am thinking of rebuilding the motor can I increase bucket size to chang motor to a 135hp of the same profile?

 

[mr 88]

Re: 115 tower of power

No you can't. What year is the 115 ,if later model it is already a 135 plus 15 crank rated hp.Marketing by Merc in the late 80's,did not want to pit the new v6 against the L6 in having them rated the same hp

 

[wired247]

Re: 115 tower of power

Thats not why they changed HP Ratings. USBA ratings at the crank started in the early 80's. The inline 6 115 HP of the late 80's was the old 150 HP crank rated motor minus 5-10 HP because of the lower compression ratio and back draft carbs. 140 crank HP or so or 115 honest prop HP. The late 80's 135 V6 was 135 HP at the prop after 1982.

If anything the USBA horsepower rules were a real concerted effort to get away from the "marketing" that OMC and Mercury had been doing for years building motors that bore no resemblance to their stated HP. The 235 HP OMC crossflow comes to mind.

In any case you cant make a 115 into much of anything other than a 115. If its an early 115 thats what became the later 90 HP. There was a major difference between the early 115 block and the 150 block. All the inlines were 99 cubic inches and the 150's had porting in the block that helped the cylinders fill better that cannot readily be adapted to the early 115 block. If its a late 115 block you can boost the HP a few by doing a little work to the carbs and changing pistons IF you can even find them. High dome ported pistons are getting real hard to find any more. If you put high domes in a late block you can wake it up quite a bit but you will be using at least mid grade if not premium gas.

 

[canoemang]

Re: 115 tower of power

Get a bore gauge and check it, you may be able to get away with a hone job on the #3. you really cant do to much to these TOP, they came wound pretty tight from Merc to begin with.

Any idea why you stuck #3?