difference in vmax 225 and 250

[H2racer]

could someone tell me what the difference is between the 3.1L 225 and 250. It seems to me that a 225 could easily be upgraded to a 250 with factory parts. I am thinking about doing some work to my 225 so any help would be greatly appreciated.

Thanks,

Nick H.

[vector mike]

The difference is about 25 HP! Just kidding. I'm not sure on those but on the older 175 and 200 2.4 Mercs it's port timing which is not a bolt on thing.

[LJL]

Yammies? According to some literature the new VMAXs have differences in porting and ECM. If simplified, it means that it's easy to upgrade the 225hp but also more expensive than buying the 250hp. So, better to buy the 250hp, if you want one. Contact Hydrotec Marine.

Hydrotec Marine

LJL

[H2racer]

I already have a 225 and can't really change to a 250. Has anybody done much with the yamahas as far as performance? I was talking to wayne taylor about getting a reed block and working the heads and he said from his experience the 250s responded better to mods. He thought that the 250 may have a better exhaust tuner? If its port timing I wouldn't mess with that I was just thinking it might be something simple. I'm not looking for a race enging or anything this is my full time fishing boat and I can't leave well enough alone lol.

[LJL]

Contact Hydrotec Marine. They have the experience and can tell what suits your requirements. They also have phase kits and bolt-on hiperf parts.

LJL

[Adam McKeon]

h2racer , if you didnt find out anything i can tell you this and its pretty easy to change.
compression ratio is6.2:1 on a 250
6.0:1 on a 225
I would still call hydro tech

[Markus]

I remember having read somewhere that the porting is different - don't know about the exhaust, but I would expect it to be different too.

Hydrotec has a kit for taking 290 hp out of a 3.1 l Yamaha, but it sure won't hurt to talk to Wayne Taylor as well.

I am quite sure that these engines run 87 octane gas stock, so there is a lot of potential for raising compression.

Remember, though, that this is a long-stroke fishing motor that does not like high RPMs.

[VectorPat]

I looked it up today on the parts list..The blocks,Heads,ECU and Reeds are different..

[H2racer]

thanks guys,

I am trying to spend as little as possible but 290hp sure would be cool.

When doing these mods will the ECU add extra fuel or will I have to change fuel pressure or something?

[VectorPat]

From what I had heard the O2 sensor will adjust the fuel when the mods are done..How much it will, I dont know..The Hydro-tec guys would know more about that..