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-   -   Mercruiser 7.4 Replacement/Upgrade (https://www.offshoreonly.com/forums/restorations-upgrades/373453-mercruiser-7-4-replacement-upgrade.html)

Scottd21 09-26-2021 02:03 PM


Originally Posted by phragle (Post 4807047)
the 496 8
1 is the red headed bastard step child of the boating world... You dont want that.

What's wrong with the 496, I heard it was a beast and newer than the 502.

bajaman 09-26-2021 02:46 PM


Originally Posted by Scottd21 (Post 4807051)
What's wrong with the 496, I heard it was a beast and newer than the 502.

A lot of folk simply don't like them...basically the internals (crank, rods, etc) are not anywhere on par with a 8.2 (502 cid) engine. It originally wasn't really intended for marine use, more of a 'truck engine', if you will. With that said, there are a shiite load of them out there and some perform very well. A friend of mine has a 232 Baja with a 496 Mag H.O. and it is a VERY nice running boat.

AmiableDave 09-26-2021 03:17 PM

Worth a read.

http://www.perfprotech.com/blog/boat...54-496-repower

bajaman 09-26-2021 04:10 PM


Originally Posted by AmiableDave (Post 4807060)

Thanks! Just added to my Favorites.

cheech 09-27-2021 09:31 AM

BTW, what do you mean by stuck? Did you ground the boat?

Michigan Motorz list 2 new base 7.4L engines. Whether they have them in stock or whatnot due to today's circumstances I don't know.
To each their own, but unless you're a tinkerer and like fooling with it in the driveway for something to do.
A 2001 Searay 260 isn't something I myself would spend a lot of money or time on to repower with "substitutes" when simple options are available.
Get it done and be back to boating as economical as possible! YMMV

https://www.michiganmotorz.com/produ...marine-engines

Unlimited jd 09-27-2021 09:46 AM

I remembered that 6 or so years ago I repowered a 260 sea ray with a 6.2 carb. It was a couple mph slower, and wanted to cruise at a slightly higher rpm. Seemed to run best 3800-4000 where the old 7.4 was fine at 3300. The small block seemed to fall off plane easy if you ran slower.

Scottd21 09-27-2021 12:29 PM


Originally Posted by cheech (Post 4807150)
BTW, what do you mean by stuck? Did you ground the boat?

Michigan Motorz list 2 new base 7.4L engines. Whether they have them in stock or whatnot due to today's circumstances I don't know.
To each their own, but unless you're a tinkerer and like fooling with it in the driveway for something to do.
A 2001 Searay 260 isn't something I myself would spend a lot of money or time on to repower with "substitutes" when simple options are available.
Get it done and be back to boating as economical as possible! YMMV

https://www.michiganmotorz.com/produ...marine-engines

Sorry not literally. I heard a clicking noise that got louder and louder and engine slowed down and conked out then wouldn't turn over. Michigan Motorz emailed me back a 7.4L Vortec marine engine (never heard that name as described for my engine) based on my engine SN for $7,000. It sounds great my only concerns are the engine is 20 years old and I've had a couple of issues in the three years I've had it. First a map sensor issue which was caused by some corrosion on the intake, then I had an overheating issue and finally the engine coupler went. If I'm putting in a new core around parts that are 20 years old and previous owner also had a water leak am I going to have more issues. This would only only be under warranty for 1 year versus 3-4 that a new engine would have.

Also while $7,000 sounds great when you add the extra costs and parts needed plus labor how much do I really save is the question.

Thanks,

Scott


AllDodge 09-27-2021 12:55 PM

I've got a 26 year old 7.4 and it still runs fine. Mine being a carb motor so I have less things that can cause a running issue

Corrosion will always be around, the over heating will stay away with regular maintenance. The coupler will almost never fail if regular maintenance is done

Scottd21 09-27-2021 01:09 PM


Originally Posted by AllDodge (Post 4807199)
I've got a 26 year old 7.4 and it still runs fine. Mine being a carb motor so I have less things that can cause a running issue

Corrosion will always be around, the over heating will stay away with regular maintenance. The coupler will almost never fail if regular maintenance is done

Don't get me wrong engine was well taken care of the previous owners I believe. It looked new but previous owner did have a water leak and therefore was some rust in lower parts.

The overheat issue was actually caused by mechanics error confirmed by another mechanic (the hose was not on correctly.).

My mechanic said engine coupler was caused by taking off too fast from tubing (I've never heard of that, wasn't gunning it and didn't think that would cause it). What about people that take off quickly because they want to?

SB 09-27-2021 01:22 PM


Originally Posted by Scottd21 (Post 4807202)

My mechanic said engine coupler was caused by taking off too fast from tubing (I've never heard of that, wasn't gunning it and didn't think that would cause it). What about people t
hat take off quickly because they want to?

Lol.

More torque load is harder on parts, but it’s typically the drive that hates you more for that.

Lack of grease and misaligned drive shaft to coupler are biggest issues causing that.


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