I want to fuel inject a mercruiser 2.5 120hp engine

[O'neal]

As title states.Looking to inject my boats engine and am thinking of using either a chrysler or or gm TBI,then convert over to an electronic ignition while i'm at it.Anyone have any info or ideas on changing over?

 

[skiboarder]

Talk to b2 bomber. He can tell you all you need to know. He's a genius when it comes to stuff like that.

 

[Jesser04]

Why not just 4.3 merc in it?

 

[O'neal]

I dont want a bigger engine and the hassles that go with...wiring,different outdrive etc.I have a good engine and drive just want to upgrade and get away from a carb.The boating forums advise against the swap due to it wont be in "coast guard regulations" and will blow up,cause a big fire etc but its ok to run a carb that dumps fuel down the throat?

I would think a TBI setup would be better and safer than a carb plus the newer boats are efi so why cant I?

 

[rockdog]

I think this might be kind of a hassle. The tbi units have inputs from sensors that you can't have in a boat. The ECM adjusts fuel according to the inputs. I have thought about this on my boat, but after researching it decided a bigger engine will be less hassle.
If this was an easy conversion people everywhere would be doing it.

 

[skiboarder]

Just because not everybody is doing it. Doesn't mean it's not easy. The ecm from a Chevy uses a input from the coil to tell it when to fire. The throttle position sensor tells it how much gas. Then you need a power source. That is all you need. It is that simple. The people that make the aftermarket fi systems know this and bank on the fact that people don't understand how it all works. I have seen it done and plan on doing it to my v8 swap. It should only cost me about $150.

 

[rholbrook]

I have been researching a bigger motor in my boat as well. It's already EFI, I want 100 extra ponies. My out drive will handle it but I will need bigger injectors and I will have to have my computer reflashed

 

[Jesser04]

If you are serious call me. The guy that built trace's engine can build you a custom tune.

 

[rockdog]

Just because not everybody is doing it. Doesn't mean it's not easy. The ecm from a Chevy uses a input from the coil to tell it when to fire. The throttle position sensor tells it how much gas. Then you need a power source. That is all you need. It is that simple. The people that make the aftermarket fi systems know this and bank on the fact that people don't understand how it all works. I have seen it done and plan on doing it to my v8 swap. It should only cost me about $150.

Sorry, I guess I don't understand boat injection like I thought I did. Sounds like he could do this pretty turn key. Disregard my bs statement above, I thought there were more inputs to the ECM.

 

[rholbrook]

There is a lot involved in injecting a boat. First of all, your tank is not built for it. If I am thinking correctly, a EFI boat does not have a breather line on the side of your boat. It is a pressurized system. Possibly, you can work around that, I am not an expert in this by any stretch of the imagination. What make and size is your boat? What make is the motor in it? What will your out drive safely handle as far as horse power? You may possibly be able to get away with a better cam to get the power you are after and it would be tons cheaper. I know a lot of guys that put the aluminum heads and cams on the 350 boat motors and gain 5 to 10 mph top end and much better bottom end. I would explore those options first.

 

[rockdog]

There is a lot involved in injecting a boat. First of all, your tank is not built for it. If I am thinking correctly, a EFI boat does not have a breather line on the side of your boat. It is a pressurized system. Possibly, you can work around that, I am not an expert in this by any stretch of the imagination. What make and size is your boat? What make is the motor in it? What will your out drive safely handle as far as horse power? You may possibly be able to get away with a better cam to get the power you are after and it would be tons cheaper. I know a lot of guys that put the aluminum heads and cams on the 350 boat motors and gain 5 to 10 mph top end and much better bottom end. I would explore those options first.

Hummm, you raise some good questions? I wonder what you do with the return fuel line, since there isn't a port for that in the tank that's buried in the floor? Then there's the whole deal with the distributer from the car not being sealed. ( don't know if you have ever watched a boat burn to the water line? I have, right after it blew up!) then there's the whole Coast Guard legal deal. Whether you like it or not. Your gonna pay if they go through your boat and find your car tbi unit in a boat. You might never get checked. ( I have, they went through the whole damn thing)