Engine Upgrade

Amberjack_Jae

New Member
Jan 27, 2017
13
Florida Gulf Coast
Boat Info
2000 Sea Ray 290 Amberjack
"Paper Trail"
Engines
5.0 Mercruiser w/Bravo III
Good Afternoon all,
This is a question for all the marine engine machanics out there. I have a 2000 Searay 290 Amberjack with twin 5.0 (305) engines, making 260 hp according to the manuals. The boat also has Bravo 3 outdrives. Right now, one engine has seized and is in need of rebuild/replace. I would like to do the same work on both now if possible. The several shops I have talked to, say they have a hard time finding the 5.0 (305) block as it is no longer produced, and I should look to upgrading to 350's. SO I have looked online and found several 5.7 engine long blocks for pretty reasonable prices, ($2200 - $3800). Now I have several questions, will the outdrives handle the extra horsepower, and what would be their limit? Would the outdrives need to be modified in anyway. Is a long block the way to go, as opposed to buying a built engine which I have found anywhere from $8500-$14000, way out of my budget. I have rebuilt auto engines in the past.. so I do have a working knowledge, but never a marine engine. The prices I am being quoted are about $11000 and engine. I dont think the boat is worth that anymore.. LOL..SO.. good Idea to attempt myself? or should I keep lookng for a marine machanic. Sorry if this is long winded.. I am thinking as I go. Any help from anyone would be greatly appreciated. Also I am on the gulf coast of florida, (Ruskin) if anyone knows of a good mechanic down this way, please chime in.
Thank you all for your time and wisdom

Will
 
The B3's will do fine with the 350's... very common combination.

I'm not sure about the drive match up from 305's to 350's, I would think there would be no difference... someone here should be able to confirm.

If you have rebuilt engines before, I would not hesitate to take this on yourself if you have the place to work and some sort of lift to get them out and in.
 
No problem with a Bravo 3 and a 350.. They use B3's on the 496 motors.

A long block is a good replacement, but you should consider replacing any piece that's been exposed to salt water. ie heads, intake, exhaust, as well as the starter, oil pan, etc.
 
Be sure to check the outdrive gear ratios going from a 5.0 to a 5.7. I know they are the same on an Alpha drive but you should find out now.

I think that would be a great upgrade.
 
You can still get 305s........right from GM or any rebuilder like Michigan Motors......Just replace the 1 motor with what was in there and move on if the compression/leakdown look good on the other one
 
Looks like a marinized 305 on eBay is 1250-1700.

The one thing you’ll need to nail down is if the 350 needs a different gear ratio B3. It may be possible that the current gear ratio works, but you might need new prop sets. Just things to think about if going to a different engine.

Getting a 305 would be much more strait forward.
 
I would strongly recommend that you look at Jasper rebuilt marine long blocks. I have seen many boats on our river use these with excellent results. They have 305’s all day every day. Or, if it were me yes I would step up to 350’s from Jasper as well.
 
2808670-R1-015-6.jpg
Just a comment on the "extra HP" of the 350 CID engine. My first Sea Ray had a 350 Merc I/O for power. That was a sweet engine that ran for thousands of hours. It made 260 HP. Run a 350 at 3000 RPMs and it will last a long time.
 
You make no mention of carbed or efi. EFI upgrade from 5 to 5.7 will require ECM reflash. Carb version will need rejetting at a minimum.
 
Thank you all for your quick responses. I have heard about the Jasper engines and I am going to look at them. Also the engines are EFI not carbed. Hope to get things done soon as I am missing the water something crazy.
Thanks again all.
 
i strongly recommend the 5.7 over the 5.0 you will not be disappointed.
 
Both 5.0 and 5.7 engines probably have similar WOT specs which means that your props will be spinning at the same RPM's with either engines at the max WOT spec. That being said, the additional power from the 5.7's might allow the engines to spin those props faster than WOT specs which will mean you either have to change the drive ratios or go with more aggressive props or over-rev the engines (not good) - both of which are rather expensive propositions...
 
I'd go to 350s as price will be about the same. Have you ever heard a boater say "my boat has too much power"? The hull will like the extra horses. I got complete, new engines from Michiganmotorz in 2016 that have been great. Best pricing on complete engines I could find. The 350 should be a direct bolt in swap for your 305s.
 
The fly in the ointment will be, he will; need different injectors and a diff. ECM to power them. Neither of those are cheap.
 
He didn't mention if the boat is FI or carbs. I'm not familiar with that uears equipment so maybe it is FI. If so, then staying with the 305s would be the more cost effective route.
 

Forum statistics

Threads
112,948
Messages
1,422,805
Members
60,930
Latest member
Ebrown69
Back
Top