Yamaha 150 to 200 differences

[Jag1]

what are the differences between '89 150 and a 200 Yamaha. Thanks guys

[berg969]

the carburators and maybey the exhausts

[Markus]

Heads and porting as well.

[yamahadog]

as far as performance, you will likely botice a little more jump with the 200 and maybe some more top end.

[Ray Neudecker]

The reeds and the carbs would be the main differences.

[bully]

I experimented with this a bit with my pair of yami 150's on my offshore fishing boat. I put on a pair of 200 carbs off of some junk motors I bought.

I noticed nothing!!!!!! No difference other than less holeshot. I turned 5000 with the 150's and 5000 with the 200 carbs.

Another story, but this one worked.

My first yamaha was a 1984 150 that had a hole eaten through the back of the cylinder head and lost compression( saltwater electrolysis and crappy aluminum). I bought it this way for 200 bucks. When I pulled the head I found the aluminum around the sleave had cracked as well and wouldn't allow the head gasket to seal.

I ran the motor a couple of times and could muster 5100rpm.

I found a sunk 200 yami and decided to use my crank/rods/etc to get this girl going(this is the motor I got the replacement head off of). I bored it and put it back together as a 200 except for the 150 carbs. Guess what? She would only turn 5100rpm. What gives??? Well I cleaned up the 200 carbs and tryed them out. That was the difference. 5700 rpm solid!!!!!!!

I figure the 150's are matched all around with the ports, carbs, exhaust, etc.

Good luck
Billy

[Markus]

That is no surprise, because the 150 carbs are really small.

[bully]

yes the 150 venturis are tiny, but the diameter of the inlet and outlet are the same as the rest of the carbs.

I just figured the 200 carbs on my 150's would have made some difference on top end, but nada!!!

[Jacob]

The carbs on that engine are very small. The reed blocks are only single reed. We just change out carbs and reed blocks on a 150(parts are from a 200) made a huge difference.

[Markus]

It is the venturi size that really matters.