Engine Swap 3.0 l to 4.3 l LX

[supermax2829]

Hello! I would need some advices on engine swap. I have a Bayliner Capri 18 ft. with a Mercruiser 3 liters (130 HP) and I would like to swap it for a Merc. 4.3 LX 2000. Would it be advised? Do I need to change the outdrive gear ratio (1.96 to 1.84)? Or if I can only re-prop it? I'm not driving the boat WOT for long run since I'm on a small lake. And my last question is about the mounts... Would I have to make new mounts in the boat or it is bolt-on?

Thank you V.Much!

Max

[gonzo]

The 3.0 has a mount on the front. The 4.3 has two mounts on the sides. If the boat was designed for the bigger engine, the stringers probably has pads for the engine mounts on the sides. If not it quite a lot of work to fabricate and fiberglass them in. You should change the ratio for proper performance. Sometimes it is possible to go to a larger pitch and compensate for the ratio difference. You will also need to change the exhaust collector.

[oshberg]

I am currently doing a swap from the 3.0L to the 5.0L. I work at a stainless steel fab shop so I was able to make motor mount plates out of 1/4" ss. The only space issue that I came accross was the crank pulley was a 3 groove and would have hit a stringer. I had our shop machine it down to a single groove (I'm not using the power steering). Other wise it fit quite easily, but there isn't alot of extra room. The one question that I have is should I go with the 1.50 or 1.62 gearing for the lower unit?

[gonzo]

1.62 should work. You can always fine tune with different prop pitches.