Mercury interchangeability questions for the gurus

[BOWSER]

What powerheads will plug and play on a 1989 Bridgeport 2.4 EFI mid (not offshore)with sportmaster? I’d prefer to keep the pan and cowling, but I also realize that these were specific units to cut weight so adaptability isn’t in my favor. I’ve read that the 2.4l 150 mid will accept just about anything but tbh I apparently don’t know jack about these motors and what will adapt. Looking to temporarily repower my rig with as little headache as possible until I can get the original motor up and going. What 2.0, 2.5 or 3.0 Merc motors will drop on and keep the wiring original or close?

This isn’t a race boat or anything, so I don’t require the fastest stuff. But I WOULD like to know what options I have since these 2.4’s are discontinued by Merc. My plan is to keep everything as original as possible so I don’t have to do more than usual when I get the BP back up and going. Call it a fools errand, but I have all of the original gauges and equipment for the Bridgeport as well as numbers matching everything. Even though this isn’t a bass motor, I want it back the way it was eventually. The sound and WOW factor is irreplaceable. Don’t care how much they smoke or hate idling.

[Merc 2.5]

U can go with any 2.0,2.4 or 2.5 , 3.0 will need start changing lots of things
Btw. I like ya charger , how much those boats weigh u guess?

[ChrisCarsonMarine]

Although the mid section will accept any 2.0,2.4 and 2.5,you are limited to motors 1989 or earlier if you want to use your pan and cowl.These motors use a 16 amp charging system(or a 9),and mount the coils directly on the exhaust plate.This system will fit under your cowl.Starting in 1990 a 40 amp system came into use that mounts the coils on a bracket further rearward,and will require a larger cowl...No 3 litre will bolt to your mid,Chris

[tlwjkw]

lookin' close it looks (pretty much) ta be complete, original '89/'90 maybe, BP all tha way thru, ie: one piece adapter, bass can, offshore clamp, cle gear case.. best I can tell blowin' tha pics up..

running a stock production PH on that adapter is gonna take some attention ta tha coolin' system.. would be easier for someone with "limited" merc knowledge ta use tha two piece plates that go with whatever PH ya decide ta put on it... jus a little information ya need ta know.. even if its jus temporary...

got any pics of power head???

[BOWSER]

Merc 2.5, the NADA page says they weigh 1450. Was looking at some Gambler boats when I stumbled across this one. The gelcoat is still great with one light spot by the trolling motor and slightly light by the motor. I put a little wax on a couple of spots to see what it would do and man... The glitter came to life with just a light rub with a t-shirt. Gonna put about 2 days worth of wet sanding and buffing into it and should have a fair representation of what it looked like brand new. Somebody took care of the boat before the guy I bought it from. It’s solid as a rock and looks to be all original. Thank you btw.

[BOWSER]

Thanks, Chris. Yea I heard about the charging system and just by looking at other motors I was afraid I’d have to change the pan and cowling. It’s cool though, not a problem. Main thing is to get back on the water while I’m getting the Bridgeport machined and put back together. Planning on steel sleeves, top pinned pistons and relief cuts/holes to keep the bridge cooled. Hearing what will bolt on temporarily gives me hope because I will most likely have to buy a complete motor and steal the powerhead to have a running boat again. Thanks again!

[largecar91]

Although the mid section will accept any 2.0,2.4 and 2.5,you are limited to motors 1989 or earlier if you want to use your pan and cowl.These motors use a 16 amp charging system(or a 9),and mount the coils directly on the exhaust plate.This system will fit under your cowl.Starting in 1990 a 40 amp system came into use that mounts the coils on a bracket further rearward,and will require a larger cowl...No 3 litre will bolt to your mid,Chris

. I ran a 2.5 225 Promax under a early 2.4 T3/175xs cowling. It does fit but tight.

[BOWSER]

https://forums.iboats.com/forum/engi...-interchanging. Thanks tlwjkw. Yea I’ve been reading up on the exhaust differences and I’m pretty sure you are correct. I’ll definitely keep that in mind when switching power. Here’s some pics I got while taking the bp down. Lots of varnish and gunk in the vacuum lines and just about everywhere else but it is what it is. I’ll have it back up to code and looking good by the time it’s ready to reassemble.
The pic of the injector side was from the original owner. All of the nastiness on the midsection wiped right off, guess it was just lake scum. Got the boat in central Texas and I’m 100% sure it never saw saltwater from what I saw during the takedown.

I didnt take pics pics of the stamps on the horn/intake but they matched the block. I didn’t see any signs of the motor ever being taken down and rebuilt before aside from the .080 written in the cylinder head. The heads are stamped 080 so maybe someone at Mercury wrote it in? Here’s the compression numbers she threw.

[tlwjkw]

largecar, think chris is referend to a stock "production" type 40 amp motor that has tha coils sticking way out on back....

looks like a complete, untouched, top ta bottom hi po motor.. something very rare nowdays.. other than tha "80" which should mean tha heads have been cut 80 thousandths.. spendin' all that cash for a rebuild ya might wanna check into an "acu" for it.. tha merc ecu's and tpi's aren't known for they're reliability with any age on 'em… jmo.. good find though!

[BOWSER]

Yea, I’d agree on the A13 box. Not my favorite at all. I’ve got my eyes open for a Brucato ACU if I can find one within reason. As far as the .080... The cylinder heads have 080 cast into them from the factory. I can’t see any other reason for it to be written in permanent marker other than “like you said” being shaved a bit. Was just curious if anyone had seen the same thing on some stock ones. Guess I got my answer about whether or not the motor was gone through. Cool. Well I got a lot of questions answered today! Thanks to everyone who chimed in for the help. Gonna try to find something to drop on and then put some cash together for the rebuild. Hopefully I can get Jay Smith from JSRE to build it for me since he did a couple of them back in the day. I can put it all together myself no worries, but would prefer to let a builder assemble the rotating assembly and do the machine work on the pistons to make it survive. Can’t wait to run it myself one day. Previous owner said this prop put it in the 80’s. Looks like they hit a rock or something and then heated to prop to straighten it up. Hopefully it can still be fixed by a prop shop.

[tlwjkw]

thought ya meant "hand die stamped"?... prop is sad... but its old also.

[BOWSER]

Yea I got mixed up on words. The 080 is cast into the head with A or B can’t remember what side mercury calls side A even though starboard side is #1 for firing order.

[tlwjkw]

went thru "several" 2.4 hi po motors way back when.. so also don't remember much with tha numbers.. but nowdays doin' good ta remember where i'm at when I get outta bed....

[Baker343]

If your looking for a temporary engine replacement you might consider looking for a complete 175 or 200 2.4. PH and Mid section.

It appears that many people are repowering with newer OB's. You could use your lower unit and plug and play and resell when your BP is ready.

You would avoid the cooling issues and possibly matching exhaust. Block to 1 piece or 2 piece exhaust plates

[BOWSER]

That’s pretty much where I’m at right now aside from the center section. Been seeing some pretty legit bass motors floating around so far. My thing is that the BP will absolutely be coming back together aside from divine intervention where the block is trashed from ingesting the ring. I do know that the BP build isn’t going to be a longevity type motor and I’ll have to do all kinds of crazy stuff like shift when motor is killed etc not a prob btw. The little trolling motor I got will be more than enough to handle my light work. In your opinion, should I just basket case the center too and preserve it as well? Only reason I’m building this little motor is for nostalgia purposes. I love em and wanted one as a kid. This boat won’t see any saltwater. I have an old workhorse for that. This is my jab at counterpunching a high dollar bass boat note lol. I wanted something fast/pretty/rare. With that being said. What do you guys think of the Promax 225? Is that another race motor too or would it be worth the investment? I need a secondary motor to alternate with between rebuilds or whatever happens. I’ve heard a lot of you guys running them and saw a couple in the 4.5-5k range complete minus prop.