Engine Replacement

[coreybeck]

Has anyone repowered their boat with a larger engine/ hp?

I have a 89 Carver Montego that I have been restoring. \
The boat sat in a farmers field for over 7 years.

I put it in the water once 2 years ago, then the original Mercrusier 260 5.0 died.
One Mechanic told me it was a cracked block.
It didn't even turn when wrenching it... so it is completely seized.

Its taken me some time to find an engine.

I found a 7.4L 310/330 hp for a great price.
I have not been able to find a 260. and to be honest I wanted to put something in with a little more HP

From my understanding this larger engine was an option engine on these boats in the late 80s early 90s.

Has anyone put one of these into their Carvers?

What challenges did you incur ?

Im told the engine will or should drop right in on existing mounts because it was an option engine

[g36]

Is the other engine ready to go or do you have to swap over a bunch of parts?

[coreybeck]

Other engine is ready to go. Its on a skid with all parts

[waybomb]

Is this with an outdrive?
More horsepower means more torque.
More torque means larger load on driveline.
Also means you'll need to reprop.
If outdrive, you need to find specs for it and can it handle the torque.
If prop shaft, is it thick enough for me torque?
You may be disappointed with such a small increase in torque. And what about engine weight? Now you are changing the hull cg.
You might be far ahead by finding a nice small block, rebuild it to the 260hp soec and swap the exhausts and accessories.

[km1125]

Second all the concerns that Waybomb mentioned.

You could go with a higher hp small block, but you still have the concerns about torque and what the existing equipment might need to handle.

[coreybeck]

I understand what you are saying with regards to the torque and such.

Its a Stern Drive


The issue for me is that there aren't a lot of engine available where I am. and the ones that are available, are so overpriced
its absurd.
Im in Central Canada (Winnipeg MB) in lake country, but the market here is one where guys are putting a extremely high premium on even rebuild engines.

The engine I found Im shipping in from out east around the Toronto area where there are a LOT of engines available.
I've seen this engine, I've seen it running and the compression tests.

I know from the Carver specs on my boat that the 7.4 was offered as an engine option for the boat. However most were outfitted with the 260.

My thought was that I always wanted to upgrade and slightly increase the HP on the boat regardless.

[waybomb]

Once again. It's going to get real expensive if you blow the drive. You need to make 100% certain on whatever drive you have. I've never heard of a production boat overbuilding anything.
For starters, you'll need a different prop. Then when you blow the drive, you'll need the entire larger set up, and another prop.
You'll be dollars behind and may pick up 5 mph, and burn a bunch more gas.
Get the serial number of the drive and determine the build specs for torque. Then determine the torque of your new engine. Do this before you spend money. Drives aren't cheap.

[coreybeck]

I have a spare bravo drive that fits with the 7.4

My Mercrusier 260 block is cracked so I can always part out the rest of the engine and my Alpha stern drive
So I should be fine

[bud37]

Just gonna add here.

I would make darn sure that the engine bed stringers and the transom are in good enough structural shape to handle the upgrade or even for use with the regular engine/drive package. Check for rot behind the glass.

If the boat has structure issues it still won't be worth much no matter what you upgrade.

[waybomb]

What we are telling you is that if you go through with this, be prepared for an outcome that may not be ideal.