Hopping up a 40 Magnum?

[rickou812]

Any tips or tricks to tweak out a Mariner 40 magnum 4cyl. It seems these little 4cyl engines should make a ton of power fairly easily.

Thanks in advance,
Rick

 

[Chinewalker]

Re: Hopping up a 40 Magnum?

Not really much you can do. The Magnum 40 is actually pretty much the old Merc 50 horse, re-rated to propshaft horsepower. If you went through the trouble of opening up the ports & intake, you MIGHT get a couple horsepower, and you probably would see little or no improvement in speed. You would be better served by either getting a larger motor, or maximizing the set-up you have now with propeller and motor height experimentation. Are you maxxing out the RPM? That motor likes to rev in the high end of the RPM band (5500 or so).

 

[rickou812]

Re: Hopping up a 40 Magnum?

Not really much you can do. The Magnum 40 is actually pretty much the old Merc 50 horse, re-rated to propshaft horsepower. If you went through the trouble of opening up the ports & intake, you MIGHT get a couple horsepower, and you probably would see little or no improvement in speed. You would be better served by either getting a larger motor, or maximizing the set-up you have now with propeller and motor height experimentation. Are you maxxing out the RPM? That motor likes to rev in the high end of the RPM band (5500 or so).

Thanks for the reply. I have not tore into the engine yet, but looking at parts listing, they show a "40hp restricter" in the carb microfish. I also had heard of restricters in the reeds..

Thanks again,
Rick

 

[Faztbullet]

Re: Hopping up a 40 Magnum?

The restrictor noted in breakdown was limited to commercial & promotional engines. They where never installed on consumer egnines that I know of. Never heard of "reed restrictors" and that engine makes about 48hp. You can get about 60 hp out of it with some major mods to block,pistons,reed blocks,carbs, but the expense is higher than trading it in on engine of larger size. These mods are for engines in a limited racing class and none are "bolt on" items.

 

[rickou812]

Re: Hopping up a 40 Magnum?

The restrictor noted in breakdown was limited to commercial & promotional engines. They where never installed on consumer egnines that I know of. Never heard of "reed restrictors" and that engine makes about 48hp. You can get about 60 hp out of it with some major mods to block,pistons,reed blocks,carbs, but the expense is higher than trading it in on engine of larger size. These mods are for engines in a limited racing class and none are "bolt on" items.

Thanks for the info, will save me the trouble of looking for the restrictor..lol

Thanks again,
Rick