150 JOHNSON CAN YOU AD 175 CARBS AN CHANGE TIMING TO MAKE 175 ?

[cat-n-tenn]

I WAS TOLD THAT YOU CAN PUT 175 CARBS ON 150 ENGINGE AN CHANGE TIMING TO MAKE IT A 175........IS THIS TRUE ?

MY CAP KEY ON MY HOME COMPUTER IS BROKE SO I AM NOT YELLING AT ANYONE

THANKS

[cat-n-tenn]

EVINRUDE ENGINE.......... DONT KNOW WHY I PUT JONSON

[cat-n-tenn]

ALSO IT IS A 1993 OR 1994 150HP TRYING TO GET MORE SPEED ON A 277 JAVELIN

[Neveredge]

No, the porting and heads are different.

[Bassmeister]

Shawn is right, if that was all there was to it ,everybody would be flippin 'em magic switches under the cowls of the 150-200's!!!

[Lockjaw]

I actually researched this quite a bit. If it is a Fast Strike, then it already has the bigger carbs. The carbs on the fast strike 150's and 175's are the same, and larger then on the regular 150's.

The heads on the fast strike motors are also different from the regular 150's as well, but the heads are the same as far as Fast strike 150's and Fast strike 175's.

The porting difference is the exhaust port on the 175 is raised a little higher then on the 150. The 175 makes its peak HP at about 5700, the 150 at about 5400, on a Fast Strike engine.

If you have a standard 150, which I have, swapping to the larger carb's is a good cheap modification. I picked up a good solid 200 rpms on the top, you don't have to make any jetting or timing changes, you just have to set the idle in gear in the water. I set mine with it strapped down to the trailer. It also runs a little better through the mid range and top end.

Get the carbs and throttle bodies together, there is also a small diff in diameter of the TB's on the small versus large bore carb.

If you take some pictures of the bores of your carbs, I can tell you if they are large or small. It's an easy swap. I could do it in about 30 minutes now.

And just so you know, most people say the 150's have better low end then the 175's.

[ep72]

This is good info. i"ve always wondered about changing my f/s 150 to a 175.