converting 250xs to 300xs

[shesha]

Hi. I have apair of 250xs engins and i want to upgrad the power head to 300xs. Now my qustion is can i use all the accesories from my 250xs to the new 300xs powerhead. I know that the ecm is different and i have to switch to the 300xs one's . What else i should consider.


Thanks

[DonG]

Hi. I have apair of 250xs engins and i want to upgrad the power head to 300xs. Now my qustion is can i use all the accesories from my 250xs to the new 300xs powerhead. I know that the ecm is different and i have to switch to the 300xs one's . What else i should consider.


Thanks

The crank is different (3.0L to 3.2L), heads need to be machined to accept the longer stroke, ECM, and a few other minor changes.

[shesha]

The crank is different (3.0L to 3.2L), heads need to be machined to accept the longer stroke, ECM, and a few other minor changes.

Thanks for your help, what i meant is i am going to buy two 300xs powerheads from mercury. And i want to use the existence electrical, manifold, injection throtel body. Etc ... From my 250xs engins. Can i do that. What things need to be changed.


Thanks

[hydrostream1]

I would talk to Dave bush.racing on that one.

[shesha]

i tried to compare most of the parts from mercury catalog parts number and they have the same numbers except for the fuel pump. and the ecm but i want to make sure before i go and order one.

[merctech5591]

As long as u are using the new style vst everything else is the same. Except internals of course and PCM . That's going to be an expensive power head . Last time I priced one they were over 8k

[Badbait]

Is the wiring harness the same so that I can take off my 250XS and bolt up a new 350 XS and plug and play.