mercruiser 3.0 /4.3 upgrade

[dougt7742]

hi guys have a 99 searay 180 br with 3.0 mercruiser coupled to alpha 1 gen 2 leg and am thinking of repowering with a 4.3 v6 . Has anyone done this job? are bellhousings flywheel and coupling all need to be changed ? are leg ratios ok or need changing, or can a higher pitch prop do the business?. any other issues you can think of ? all help relly appreciated cheers dougt

 

[Bondo]

Re: mercruiser 3.0 /4.3 upgrade

Ayuh,... Your hull won't have a motor bed to mount the front mounts into,...
You won't have a Y-pipe...
And, yes, the outdrive ratio will need changing, a bigger prop Won't cut it...
And,...
There's the possibility the Motorbox won't fit over the wider motor....

A Better answer is to sell it,+ Up-grade to the boat you Really want....


Btw,... Welcome Aboard...

 

[180shabah]

Re: mercruiser 3.0 /4.3 upgrade

Ditto - can it be done, sure. Is it worth it, probably not.

 

[stonyloam]

Re: mercruiser 3.0 /4.3 upgrade

The 4.3 is about 200# heavier than the 3.0 and in a 18 foot boat the added weight could be significant. Having considered a similar project, Bond-o and 180shabah's advice is pointing you in the right direction.

 

[JimMH]

Re: mercruiser 3.0 /4.3 upgrade

It would be more economical to trade boats. Just my two cents.

 

[purpony]

Re: mercruiser 3.0 /4.3 upgrade

I was thinking of doing the same to my 17ft searay. I am in the process of gutting it now for a full resto and have the 3.0 out.... probably wont attempt it but it has been in my thoughts... the 3.0 is 135hp, the 4.3 is what, 190hp?

 

[Don S]

Re: mercruiser 3.0 /4.3 upgrade

the 3.0 is 135hp, the 4.3 is what, 190hp?

And everything on the boat is 3.0L and you need everything to be 4.3L.

Nothing a lot of new parts, a lot of money, a lot of time, and a lot of money can't cure. Oops, may have forgot to say Lots of Money.
The only thing that is the same is the transom shield ............. maybe.

 

[purpony]

Re: mercruiser 3.0 /4.3 upgrade

i just found a local searay for sale one town over, same year as my 170 with a complete 4.3. Asking $650 for the complete boat... may look into it, maybe not.

 

[180shabah]

Re: mercruiser 3.0 /4.3 upgrade

Depending on vintage, a 4.3 can be anywhere from about 150hp all the way up to 225hp at the prop.

If you can get the complete boat for $650, it might be worth it. IF all of the hardware is in good condition. For $650 though, I am skeptical. Was it winterized, PROPERLY?

 

[purpony]

Re: mercruiser 3.0 /4.3 upgrade

Depending on vintage, a 4.3 can be anywhere from about 150hp all the way up to 225hp at the prop.

If you can get the complete boat for $650, it might be worth it. IF all of the hardware is in good condition. For $650 though, I am skeptical. Was it winterized, PROPERLY?

I know what you mean. If they guy gets back to me i may go have a look at it. We will see.