Stive2699

Hello all,

Will try to make this short as I can..

Got a 1986 Triton Dynasty runabout boat 19ft. Had original 140hp mercruiser engine in it. Would top out at 40-42mph. Engine would never run right and we got fed up with throwing money at it. Bought a mercruiser 4.3L v6 fuel injected 2bbl carb. I *think it might be 220hp. Will post pic below. Have the same outdrive that went to the 140 and same prop 19".

With the new engine today it was topping out around 45mph at 5000rpm's. Around this point it seemed like it was over reving and it felt like it was skipping..like it pick up and then lay off over and over. Guy told us not to run it over 5000 rpms. Have seen sites that say it can be ran at 4800rpms all day.

I don't understand why a 80hp increase would only do a couple miles per hour more.. seems like it would bump it more then this. If it is a 175hp I could see how the increase would not be that much. Is the upgrade on hp more for the torque side? Like the acceleration is were the real upgrade side of changing motors comes into play and not top-speed?

With the 140 we could accelerate it fully without worrying about over revving it...why does this come into play of "over revving it" with the v6 now?

Also been reading a little on re-gearing. Does this need to be done? How much?

Anyone know what prop size would be best? have a 19 inch now. Tried a used beat up 23 and it was up to 5000rpms going around 30mph.

How much do you think it would be to get one of those exhaust set ups where you can have the exhaust out of the water or in the water. Like flipping a switch to move it in and out of the water.

Dad pulls it with his mini van now. Wondering if I can pull it with my 4runner without damaging my runner. 1999 2wd toyota 4runner, 150,000+ mi, 33in tires, v6.

I don't no much of anything about engines and new to the boat scene. Please dumb down everything

Pic of engine:

http://www.boatsandoutboards.co.uk/i...s/PRO040_1.jpg

cztheman64

Well problem #1 is that you have an old boat that is not made to go much faster than 40+. Should have just gotten a newer boat. The Merc 4.3s are good motors i worked on a lake and they work great on the rental boats until someone tries to run the boat up on dry land... but thats another story!

Those motors in the boats that i worked with did about the same for top speed, it was around 45-50. And that was for a 2007 Bayliner same size boat. The hull design has a lot to do with the speed you will get out of the boat and the older style boats such as yours will not be fast unless you turn it into a jet boat with a big block chevy motor. that will get it moving!

Your 19" prop will probably get you the best performance from the motor, although a 21" might get you a little more since you said the 23 was too much.

the exhaust set up is Captains call and i have that in my boat but i always have the exhaust blasting and it sounds great coming from a 350 Merc! I would recommend Corsa Exhaust for marine performance.

And as far as towing, you should be fine as long as you dont back down any steep boat ramps!

Hope this helps!

Stive2699

Yes, it all helped a lot.

So we do not have to change the out drive or whatever its called to match the new motor? (re-gearing)

I dunno if the captains call is for this boat.. maybe if it was newer.. not a cheap mod! haha.

thats awesome if I can tow it with my runner not straining the motor to much.

will try the 21"...the 23" was pretty beat up. might just stick with the SS 19" tho.

Thanx for the help cz

if anyone else has any more info let me know.

Stive2699

Just noticed you were from kennesaw. Im in snellville and we usually go to lanier. It was so freakin choppy this past monday. any kinda suggestions on what lake to hit up to wakeboard/ski? Im guessing any but you just have to be there pretty much before the sun comes up to get alot of riding in.

anyways thanks again, later

cztheman64

A regear probably would not be a bad idea, but what drive do you have on the boat?
True the captains call would not be a cheap mod but you could find the parts and do it yourself if your up to it. Probably a day or two work.
The 4runner should be fine as long as your not trying to climb any mountains.. lol.
you might be better off with the 19 but if you do try a 21 just try and get a cheap used one thats in good shape.



Well lanier is the WORST on the holidays. I never go out on the holidays bc thats when all the people that cant drive boats go out and unless you have a mega cruiser then you and your boat will usually take a beating. But if you can get up there during a week day then you could pretty much ski up and down the lake, I personally ski no matter what, usually one good run from the dam up to gainesville marina.

Good Luck,
Cam