mercruiser inline 6 with outboard

[finx]

I have a trihull boat im restoring to its former glory. The prevoius owner took out the seized mercruiser motor and put in an inline 6cyl from a GMC truck. Here never ran it after the swap and the boat just sat there. A few questions:

1. I know that mercruiser had a longer dipstick for the oil to be pumped out. is there any other difference between motors?

2. If i swapped out the engine for a small block v8, what would be the repercussions? Would that be too much weight in the back? What if I put the 2 batteries in the front for better weight distribution? Would my outdrive work on a V8?

I'm doing a complete restoration from the ground up on this boat so I can put the motor mounts anywhere i want them to be.

 

[tpenfield]

Re: mercruiser inline 6 with outboard

I have a trihull boat im restoring to its former glory. The prevoius owner took out the seized mercruiser motor and put in an inline 6cyl from a GMC truck. Here never ran it after the swap and the boat just sat there. A few questions:

1. I know that mercruiser had a longer dipstick for the oil to be pumped out. is there any other difference between motors?

2. If i swapped out the engine for a small block v8, what would be the repercussions? Would that be too much weight in the back? What if I put the 2 batteries in the front for better weight distribution? Would my outdrive work on a V8?

I'm doing a complete restoration from the ground up on this boat so I can put the motor mounts anywhere i want them to be.

OK. let's make sure that what ever engine ends up in the boat and where ever the batteries land, it is all marine components and according to proper marine ventilation standards, etc.

You would hate to blow yourself out of the water on your first outing after having put all sorts of work into the boat .

If you put the V8 in there, maybe you could also attach some wings, cuz it will fly. Might be too low in the stern though.

 

[finx]

Re: mercruiser inline 6 with outboard

so I should replace it with a mercruiser motor? I see one on craigslist for $300 bucks. It might be fuel injected which wouldnt work for me.

 

[Don S]

Re: mercruiser inline 6 with outboard

I moved this from the Mercury outboard forum, so at this point I'm not sure what you are asking or if you know what you have.

The outdrives have different gear ratios for different sized engines. Do you know what the gear ratio is? Are you sure this is a truck engine and not a Mercruiser? Mercruiser did use the inline 6 Chevy engine for a bunch of years. What year is the boat? Pictures of your engine and drive would be a big plus right now.

 

[stonyloam]

Re: mercruiser inline 6 with outboard

Disclaimer, all IMHO. If the boat is under 18 feet you might have some weight distribution problems because the V8 would be a couple of hundred pounds heavier. Putting the batteries up front would be unwise. The 6 cyl truck motor should work just fine, but it MUST have a marine starter, alternator and fuel pump. A 6 may have been the original, take a look at the front motor mount, and see if it looks original. Your current outdrive will NOT work with a V8. The GM 6 has a great reputation here and most of the folks that have them love them. Some more info on the engine would be nice, and the year of the boat. Hope this helps a little. Good luck.