1999 Bayliner Capri 1850 LS Bowrider Seized motor, Auto 2.5L GM/Mercruiser 3.0 SWAP

[latunguley]

I have found that a regular GM 2.5L motor and a Mercruiser 3.0 Motor share quite a few matching gadgets such as distributor hole, inspection pans and gaskets, mechaical fuel pumps location, head bolt tourque sequences, front motor mount bolt holes, My problem is i am layed off and have been for some time. I want this boat to jus run again for now. I will be buying a 4.3 V-6 motor package once from Michigan Motorz once ive been back to work for a year or two? Right now i just want this boat to run again. I have had folks tell me that a GM Pontiac Firebird 2.5 L motor will fit in palce of the 3.0 mercruiser motor and i have had them tell me NO it will not go in place of the 3.0 mercruiser motor? I have with me a GM manual for the 1984 pontiac 2.5L motor and rebuilld and i have the 99 era Mercruiser Clymer manual for rebuilding the motor here. If anyone has attemped this swap out before please let me know the true answers. Will it not or will it swap into my 99 bayliner capri 1850 LS??

 

[NYBo]

Re: 1999 Bayliner Capri 1850 LS Bowrider Seized motor, Auto 2.5L GM/Mercruiser 3.0 SW

Even if it fits (I can't say either way for sure), there will be a number of problems. The cam profile will be wrong, and a marine motor doesn't use vacuum timing advance. You will be giving up .5 liters, along with the torque and horsepower that go with it. While I'm sure the 3.0L provided satisfactory performance, a 2.5L may not.

Do you still have the seized 3.0L? If the swap is possible, the only way to make it economically sensible is to swap over all the marine parts (distributor, starter, alternator, carburetor, exhaust manifold and riser). If those parts aren't interchangeable between these two motors, the cost to do the swap and end up with a safe boat will probably be more than what it would cost to fix the 3.0L.

 

[latunguley]

Re: 1999 Bayliner Capri 1850 LS Bowrider Seized motor, Auto 2.5L GM/Mercruiser 3.0 SW

Yes the 3.0 motor is still fully intacted with my boat, as i was getting ready to trim a large maple tree in my backyard to hang a chain and chain hoist from a rather sturdy and thick limb high up in the tree to pull the motor with. I have a Jet brand 2 1/2 Ton chain hoist. And i was looking to insrall all the original 3.0 hardware into and on the 2.5L. such as you have mentioned. Living in North Central PA the 3.0 mercruiser is not very common used. And the 2.5L car motor is abundant and all around. I just want it to run up and down the West Branch of The Susquehanna river again here for the summer. Next Year i want to Michigan Motorz the boat with a new Crate 4.3 V-6 complete package deal. This is a just for now ordeal on a very small shoestring budget. I'vce been layed off for a long time. Not like over a year but October will be a year. Hope to be back to work somewhere by then. And i am seeking this info just to get me up and on our local river for this year. Not planning on pulling skiers or tubes this year. Just fishing, chicker picker upper maybe??? Who knows? Whem my local A&A Auto parts store looked up the head gaskets for both motors they had different part numbers yes. But the schematic appeared very similar or the same. So thats what lead me to ask if i could bolt the 3.0 head and intake/exhaust onto the 2.5L motor and use the 3.0 distributor, and use the 3.0 everything hardware?? If there are any other ideas or resources please. I welcome any helpful info. Also if you have a cheap shoestring budget priced 3.0 please use the PM messaging system for that. Thanks I am willing to travel out to as far as Hempstead L.I. N.Y. The trouble with my 3.0 is i can not even trouble shoot common issues with the engine being locked up. Its so tight i wonder is it even posible to remove the motor without being able to turn the flywheel to gain access to the flywheels bolts? Thatcould get ugly real quick?? Maybe i should be dissambling the motor part by part from the air cleaner down?

 

[NYBo]

Re: 1999 Bayliner Capri 1850 LS Bowrider Seized motor, Auto 2.5L GM/Mercruiser 3.0 SW

Have you tried removing the spark plugs before trying to turn the motor? It may be hydrolocked. If that doesn't work, just for ha-ha's, try filling the cylinders with a 50:50 mix of transmission and acetone. Screw the spark plugs back in and let it sit for a couple of days. Remove the spark plugs again and try turning the motor.

 

[latunguley]

Re: 1999 Bayliner Capri 1850 LS Bowrider Seized motor, Auto 2.5L GM/Mercruiser 3.0 SW

Does anyone know if a 1968 Mercruiser 3.0 engine will mate up to my 1999 Mercruiser 3.0 engine asseccories? I found a donor boat today for 200 cash. Says it ran 5 years ago when the man parked it. Had it run enough two summers ago to show a guy that it ran. And Its a mercuiser boat all the way. You can visably see mercruiser everywhere on the boat. And the motor looks like mine, Except the Inspection cover is made of aluminum instead of stamped steel. The distributor is points oriented instead of like mine with Electronic ignition. Same Mercuiser outdrive unit and props except it does not read Alpha One anywhere. But does read mercruiser on it. If any of you have been through this kind of swap please let me know if i can just use the long block or maybe just even the short block. This is good news to an extent. Better than trying to swap in a GM S-10 Pickup 4-Tec 4 cylinder inline motor? Right? Thanks to all that have replied already. I apreciate your time and efforts very much!

 

[latunguley]

Re: 1999 Bayliner Capri 1850 LS Bowrider Seized motor, Auto 2.5L GM/Mercruiser 3.0 SW

Does anyone know if a 1968 Mercruiser 3.0 engine will mate up to my 1999 Mercruiser 3.0 engine asseccories? I found a donor boat today for 200 cash. Says it ran 5 years ago when the man parked it. Had it run enough two summers ago to show a guy that it ran. And Its a mercuiser boat all the way. You can visably see mercruiser everywhere on the boat. And the motor looks like mine, Except the Inspection cover is made of aluminum instead of stamped steel. The distributor is points oriented instead of like mine with Electronic ignition. Same Mercuiser outdrive unit and props except it does not read Alpha One anywhere. But does read mercruiser on it. If any of you have been through this kind of swap please let me know if i can just use the long block or maybe just even the short block. This is good news to an extent. Better than trying to swap in a GM S-10 Pickup 4-Tec 4 cylinder inline motor? Right? Thanks to all that have replied already. I apreciate your time and efforts very much!

Ok now that ive fully viewed both engines inside the s-10 pickup and in my boat. I clearly see the differences in the two. The blocks seem the exact same. Distributors are in diff locations. Starters are same. I have since found a 1968-71 fiberglass boat 3.0 points motor. Mine is a 1999 3.0 elelctronic ignition. Some have said YES absolutely, some have said NO WAY! Not gonna work at all?? So now i'm more confused than i started with. Anyone ever utilized a old school 3.0 points motor and swapped it into a 1990's newer boat? Would that work?

 

[XiViperI]

Re: 1999 Bayliner Capri 1850 LS Bowrider Seized motor, Auto 2.5L GM/Mercruiser 3.0 SW

With the motors its simple. If everything off the new motor will bolt to the old block you should be fine. I don't think vortec heads are made for 4 cylinders so should be same pistons and heads. Swap everything that bolts to the block. Distributor intake exhaust accessories. Good luck. Don't think too many swap from new to older. So may be limited response.