19ft 4.3 omc questions, slow?

[brian102]

here is the two pictures i have of my boat as of now, can get tomorrow of it tomorrow. everything is fine when there is only a couple people in the boat, but if say you get 8 in there (wich is max capacity) it wont plane or if it does it takes forever at wide open throttle! has hesitation sometimes taking off so ordered a new carb kit for it, has anyone else had this problem with a boat similar? is it just the fact that the 4.3 is to little of motor for the boat? it does set pretty deep in the water. as far as i know it has original prop on it, dont have numbers off it because its sitting in water right now, but hopefully pulling it out tomorrow. it has the two barrel Rochester carb number 17085008. and tips or questions! thanks


http://s110.photobucket.com/albums/n106/brian102/boat omc/

 

[180shabah]

Re: 19ft 4.3 omc questions, slow?

A 4.3 should move that boat around pretty well. However, your big issue is sometimes you hae 300-400lbs of pax other times you have 1000-1500lbs. That is a HUGE difference and will most likely require two different props.

What is you current WOT performance when light loaded? When heavy loaded?

 

[brian102]

Re: 19ft 4.3 omc questions, slow?

well according to the gauge in the boat (not gps or anything) me and a friend, max i have seen was 35mph thats trimming up a little you can tell the motor is running alot better then, 4-4200 on rpms just me and a friend. speeds when loaded are just slightly slower but takes alooot more to plane off, when just 2 people its easy comes right out of water, but if more than two, you gotta hold it all the way down for a little bit

 

[danfinn]

Re: 19ft 4.3 omc questions, slow?

My 19' cuddy with 4.3LX is really slow getting up on plane with 7 or 8 people too. I've always just assumed that this was expected.

With 2 - 3 people it gets up on plane pretty quick and will hit over 40 MPH if I really push it. I think I'm running a 19 pitch prop.

 

[180shabah]

Re: 19ft 4.3 omc questions, slow?

If your WOT is only 4k, then something is wrong.

Start by checking out the "engine can't reach WOT" thread in the adults only section.

Could be engine performance related, could be over propped, could be a little of both, but the check list will help you get to the bottom of it.

 

[brian102]

Re: 19ft 4.3 omc questions, slow?

just an update just pulled the boat out of the water and the prop on the boat is a 14 1/2 x 18, i do have another one on the shelf as far as i can tell it reads 14x19 the one on boat now is stainless, the other is aluminum, carb kit should be here tomorrow, is there any good diagrams to look at for that carb or is it pretty simple, the only carbs i have done are the ones on my banshee, so 2 stroke have done them many times.

forgot to mention the numbers on the prop on the boat is 394752

 

[180shabah]

Re: 19ft 4.3 omc questions, slow?

Something is not right. Either the drive is geared wrong, or the engine is weak.

FWIW - my 4.3 spins a 21' Hustler all the way to 4800 with our normal 400lb passenger load. It still does OK when the load approaches 1000lbs.

 

[smarks]

Re: 19ft 4.3 omc questions, slow?

I've got a boat very similar to yours, same engine, same length. I have a 17" pitch prop and with two fatties aboard she hits about 42 to 44 mph at 4300rpm.

So I don't think your very far off, take a look at things after the rebuilt carb is installed. I think your prop is fine as well. If you were to use the other prop you have you would be lowering the RPM and taking you out of the power curve.

Steve

 

[brian102]

Re: 19ft 4.3 omc questions, slow?

motor weak as in bad compression? or something else, i can do a compression check tomorrow im guessing around 120 it should be or?