THANK YOU140 INLINE MERCURY 6CY

FIRST OFF I WOULD LIKE TO SAY

FIRST OFF I WOULD LIKE TO SAY THANKS TO EVERYONES HELP ON TROUBLE SHOOTING MY GRANDFATHERS 115HP MERC.I FOLLOWED CHRIS"S PROCEDURE AND IVE BEEN SKIING EVER SINCE!!THANKS AGAIN.I JUST PICKED UP A REBUILT 140 MERC INLINE POWERHEAD IT WAS A TOTAL REBUILD WITH NEW PISTONS.IVE HEARD OF SEVERAL MODS I CAN DO WITH THE EXHAUST ON THE BLOCK AND THE MID SECTION THAT WILL GIVE ME A LITTLE MORE PERFORMANCE...I JUST DONT KNOW WHAT THE MODS ARE..ANY IDEAS??I ALSO HAVE 150HP AND 140HP CARBS..WITCH SET WILL GIVE ME BETTER PERFORMANCE??I WILL BE RUNNING THIS ON A 17FT HYDROSTREAM VECTOR.ANY INPUT WOULD BE APPRECIATED OR A POINT IN THE RIGHT DIRECTION WOULD HELP.THANKS

"Anytime you are looking for a

"Anytime you are looking for a direct bolt-up enhancement to an existing engine, you are in for alot of homework.

Usually, a horsepower increase will result if your motor can "breathe and exhale" easier (within it's limitations).

On most outboards simply going with a larger exhaust will squeeze out maybe 10% greater horsepower. To relate this to a small outboard as an example, if you throw a 15 horse exhaust tube on a 9.9, it will produce upwards of 12 horses. To get up to the full 15, you need to change the carb as well.

However, that will only work since they are both based on the same 16 cu in engine, with all else (save the carb/exhaust) being identical.

An older 9.9 (12.8cu in engine) can never make 15 horses unless you want to bore out the engine.

In your case, I would ask, why are you looking for the increase. From 140 to 150 horses you are looking at what, maybe 9% - something you would never notice in a practical application.

If you were doing it simply because "the parts fit" and were available, that's one thing - but to do that build on purpose seems almost pointless.

So do your homework - find out what other horsepowers (if any) were based on your engine block - that will determine what you can do with it. If you can find an exhaust plate that will fit, from a higher horsepower, that's a good start.

Simply changing the carbs will likely just cause it to spit unburnt fuel or totally flood on you..."

GRAHAM..THANK YOU FOR THE IMPU

GRAHAM..THANK YOU FOR THE IMPUT.WHAT I AM CURRENTLY RUNNING IS A 115HP INLINE AND ITS TIRED AND I WAS PLANNING ON REBUILDING IT OVER THE WINTER.BUT I CAME ACROSS A REBUILT 140 INLINE (POWERHEAD ONLY)THAT A DEALER GOT STUCK WITH AND I BOUGHT IT FOR FAR LESS THAN IT WAS GOING TO COST ME TO REBUILD THE 115HP.I ALSO WAS GIVEN A 140HP MARINER AND A 150HP MERC INLINES BOTH OF THESE ARE COMPLETE MOTORS BUT HAVE BURNT PISTONS.I WAS LOOKING TO BEST UTILIZE THE PARTS AT HAND FOR THE BEST BUILD.IF I SWAP THE 150 EXHAUST PLATE AND CARBS TO GET MORE HP I WILL BUILD IT THAT WAY.IF I CAN SWAP THE REEDS FOR MORE HP I WILL BUILD IT THAT WAY.SOUNDS LIKE YOUR RIGHT I HAVE TO DO MORE HOMEWORK.SOUNDS LIKE I HAVE TO RUN ALL 3 SERIAL # AND SEE WHAT THE SPECS ARE ON THE BLOCKS TO SEE WHAT I CAN SET UP ON THE 140REBUILT BLOCK?? THANKS ED

"Yes Ed, thats exactly it. Th

"Yes Ed, thats exactly it. The 140 may well be the highest horsepower built on that particular block (cu in wise). If so, not a whole lot you can do with it to bump it up..

Good luck.."

Also to change the reeds on th

Also to change the reeds on that motor you would need to pull the crank!