my firend just got an 1989 24ft Doral Tara. Got it from a friend.

about 7 mins into he first test run on the lake the engine temp went way up and a massive smoke show issued from the engine bay. clearly it wasnt getting any watter circulation.
turned out the impaller was completely out, only the heart of it was left. changed that and put in a new thermostats and the engine runs great cuz sbc.

now wats going on is the fact that the boat came with a pretty torn up propeller witch was 14inch by 19pitch and it also came with a 14inch by 21pitch spare prop. so before even going for the first test we had swaped out the 19pitch for the 21pitch. Once we had the engine running good at the dock we went out for the second test run. and the boat just wont get to cruising speed. the engine doesnt rev past 3200 rpm. im pretty sure it because of the prop but then again im no boat specialist and i cant find wat is the original prop this boat came with. went trough all the owners paperwork thats in the boat and nowhere does it mention wat prop is recommended for the boat.
i did find a merury 350/alpha1 prop chart listed with boat lenghts/weights and top speed.

in that chart it does say that a 14'' by 19pitch prop would be suitable for a 3000-3900lbs 20-23' boat.
the next class of props is for 3500-4700lbs 22-26' boats

im guessing this boat is in the 3800lbs range, and will be having at least 2-8 poeple on board everytime it cruises.

or maybe im going crazy with all this prop bullshit and the carb secondaries are not opening

3 blade? HP rating?

forget the prop for a minute.... 3200 is your biggest problem right now....

why wont it run up over 3200. is it just when its under load, or is it always.

The "Stock" prop that the boats come with is usually not great at anything. Manufacturers put in a mid range prop that can kind of work for anybody.

For Skii boats, take the wet (curb) weight of the boat and add 1500lbs. (More if you have a skii tower)

Then figure out what the HP rating and gear ratio of the drive on the boat are and then you can start looking at charts for the prop.

However, Sounds like you have bigger issues than a prop right now. The difference from 19 to 21 pitch on a prop is not THAT life changing and will not be the entire cause of what you have going on. Even with a Giant prop that sbc should come up on plane.

just a generic img to show you guys wat im working with.
kinda ironic i didnt follow the ''how to ask for help sticky''. i wonder who wrote it.

Model: tara 24ft
Make: Doral
Year: 1989
engine/transmission option: mercruiser 5.7l 260hp / alpha 1/ with 1.47 gear ratio and both props that came with the boat have 3 blades
are you mechanically inclined/have the right tools?: got plenty of beer
Issue(s): the rpm limit has not been tested without load, should be doing that tonight. im pretty sure it will run higer rpms. i didnt check the rpm when runing it out of the water but i remember hearing it reving good when my budy reved it for the strait pipe sound in the drive way, so im pretty confident the issue isnt with the engine ''fingers crossed'' (was pluged on the hose).
we put about 100L of gas in it so i dont think this is a bad gas issues, il also be checkin for bad fuel filter.

The following if of relevance
Modifications: none
Repair budget: 999999999$ as cheap as possible

This post was edited by BlueAndWhite on Jul 5 2017 10:07am

Hier tot ds la soiré aurait tu passer sur la 20 direction montreal a la hauteur de beaconsfield? Vette rouge avec rim noir ma depasser pi jai penser a toi hah. Yavais des collant coter gauche ds la fenetre en arriere

Was the boat sitting for any amount of time prior to adding gas and starting? If so, might want to go through the carb. The gas out there today is worth a fuck and tarnishes VERY quickly. There is also a new product out that I've tried (cant remember the name off the top of my head, I'll look for it later) that you can add in the gas 1:1 and run through the carb and motor so long as the motor is sucking fuel which yours is. Works great. I've used it on my mowers and shit around the house here and it does clean out the shit in the carbs.

you miss a solid 1000 wot rpm easily, does it go a bit higher with the 19?

oui c'était moi! pas des collant c le numero de derniere fois jai été au drag. je revenait de l'ile perrot mon ami vien de s'acheter une maison laba ( justemen le gars du bateau)

so i we got the boat runing in the drive way yesterday. reved it up to 4.5k easy so then i changed the prop and we went for a test ride with the busted up 14 by 19 pitch
the boat got to plane and our smiles went from ear to ear, it was still runing like shit from time to time, but afther an hour of burning fuel messing around im guessing most of the old fuel was burnt and we had ourselve a decent ride.
we where 3 in the boat at first and we had to sit at the tip front of the boat to get it to plane at first.

tldr we managed 4100 rpm with the busted 14inch by 19 pitch. and it was hard to get to plane so im guessing since there is going to be even more poeple in that boat in the future might be better getting a 14 1/2 with 17 pitch
basing my choices on this mercruiser chart that was in the boat ( bothom left section is for 5.7 260hp alpha 1 drivetrains)
the coloms go like this:
prop diameter--pitch--material--boat weght--boat lenght--top speed range--part number


This post was edited by BlueAndWhite on Jul 6 2017 01:32pm

get a ss one atleast, otherwise you'll have a hard time planing that fat berthy with that tiny engine