4.3 omc

[weasonedog]

I have a 1988 trophy hard top with a 4.3 ltr and a 2bbl carb, I replaced the engine last year with a rebuild with roller cam, when I run the boat just with my self and a full tank I have to run at 3800 rpm and if i have 3 of us in the boat i have to run at 4200 rpm and realy labors getting out of the hole, I have to get everyone to move to the front of the boat, I have also replaced the tach and some wiring when I replaced the engine, I used a hand held digital tach to make sure the electric tach was right, I have a Seloc manual and it says that the horse power is 125 at wot (4200-4600) is this normal for these boats? I was thinking of putting in a 4 bbl carb as the manual says with it the horse power will go up to 205 ?????? I have made sure that the prop is the one for the boat 14 x19, I have put a fin on the leg to see if this will help.

Thank-you in advance for you advice
Tony

 

[trophywife]

those boats are underpowered IMO,, do whatever you can to get MORE HP. then make sure you have the correct prop for your use....trim tabs will help also...

 

[scott craven]

I could be wrong, but i'm not so sure replacing the 2bbl with a 4bbl carb is going to give you
an additional 80horse power ?

 

[wolf]

A 4 barrel will help a lot but what is your WOT right now??? if its low you got to go to a smaller prop got to get more rpm out of it.
If your wot is 4200 go down to a 16 pitch prop and see what you get your going to have to try a lot of different props and yep takes time but write every thing down

WOT........
Pitch........
how fast.....
and notes on which each prop does and handles
Try a 4 blade as well more lift out of the butt and talk to a good prop guy with all your finding most will let you try different props.

Good luck Wolf

 

[Island Fish Lifter]

Agreed with Wolf..

 

[daddystoy]

Are you sure about the Seloc manual saying 125 HP? Those 4.3L should be about 190 HP with a 2 barrel carb and about 205 HP with a 4 barrel carb. You say you have a rebuild in there. You should be getting enough power. Not sure why your engine is working so hard unless that boat is particularly heavy. Agreed that trim tabs would help.

 

[weasonedog]

Hi gents
Thank-you for your input, I have trim tabs on the boat and with them down helps slightly, I have to agree that the engine puts out more than 125 hp, checked the manual again and thats what it say's, as for wot i can get up to 4600 rpm with only me and a full tank not sure with a full load as she is laboring out of the hole so don,t want to try, I have spoke to Ron at Vic prop in Nanaimo and he thinks the prop is the right one but i will maybe contact Bayliner them selfs and ask them what hp this thing has and prop should be on there, don't realy want to put a 4 bbl on if i don't have too $$$$

Thank-you
Tony

 

[albernifisher]

I have the same boat but mine had a 4cyl volvo.When I say it took 5 mins to get on plane it really took 5 mins.Ripped the volvo out,installed a pod with a 200 merc. 3 people with all the gear and it still goes 37mph

 

[TipUp]

I run a 18'6" malibu with a 4.3, 2 barrel. It used to take forever to get out of the hole, even with tabs. Replaced the prop last year with a 4 blade (recomendations of Rev in Nanaimo), it made a huge difference. Lost a little bit of top end but the torque improved plenty.....now if I could only figure out the fuel economy thing haha.

 

[Degree of Freedom]

I've got the same boat...but with a 5.0L V8. Fully loaded it still takes a while to get on plane. The 4.3L and 3.0L that many of these came with is way under powered.
This year I replaced my prop with a low pitch, high diameter. It is now a lot quicker to plane and planes at a lower speed. You lose top end speed, but I'm not trying to win any races.