THE MATRIX EFFECT

[Calfasaur]

Hi all i have a small problem. I got me a Mercruiser 4.3l V6 1989, Went for a spin on my own went fine. Could of maybe gone a little faster, but the you go however when my family joined in the fun the boat would have gone faster if we turned the engine off and paddled with our feet anyone think of any problems that it might be It has all new plugs just serviced timing fine idles fine, please help

 

[vipzach]

Re: THE MATRIX EFFECT

We need more details!!!! WOT, how high would the rpm's go, what prop, things like that!

 

[Calfasaur]

Re: THE MATRIX EFFECT

With just me in the boat it ranged from about 2500-2800rpm with everyone else in 2000-2500rpm. Not sure of the prop. Engine sounds fine just seems to lack power If the boat is in neutral it revs a goodn. Put load on to the leg power seems to fade.

 

[Hunt]

Re: THE MATRIX EFFECT

Presure test the cylinders. ( my uneducated guess would be rings or valves ), Probably could be as simple as bad gas. These guys are great and I am sure they will give more expert advise than mine.

 

[vipzach]

Re: THE MATRIX EFFECT

Has the boat had a good tune up lately? New plugs, wires, cap/rotor or points, filters, checked timing, compression test maybe needed.

 

[Calfasaur]

Re: THE MATRIX EFFECT

yep all the above apart from compression. If it is compression would the not be signs of chugging or some thing? Exhaust is fine no dark smoke or smell of burning oil, the plugs that i relpace seemed fine.

 

[vipzach]

Re: THE MATRIX EFFECT

Is this a new to you boat, has it ever reached WOT, because 2800 is too low. Look at the prop and see what size it is.

 

[Alumarine]

Re: THE MATRIX EFFECT

It could be as simple as way to big a prop.

 

[Calfasaur]

Re: THE MATRIX EFFECT

Yep new boat to me, came with a pair of spare props that seem the same size. What would be a recommended size? WOT? wot this?<br />cheers

 

[Alumarine]

Re: THE MATRIX EFFECT

WOT means wide open throttle.<br />Boats should be able to obtain a certain rev range with the correct prop.<br />Props often look the same but aren't.<br />They should have a number on the hub indicating size and pitch.<br />Someone might be able to help but need to know the size,type and maybe weight of boat.

 

[vipzach]

Re: THE MATRIX EFFECT

WOT is probly around 4400-4800, what size of boat is it?

 

[Calfasaur]

Re: THE MATRIX EFFECT

Its a 19'6 Elan Invader 1 1/2 tons? there about, just had a look at the spare props they are - 48 78122 A40 21 and 48 78118 A40L 17P not check on the boat yet though with the boat in neutral it will attain 4400-4800rpm no problem again all sounds fine no smoke or stange noises (sounds quite meaty actually)<br />P.S thanks for all your input

 

[Haut Medoc]

Re: THE MATRIX EFFECT

I would try about 14Dx17p.....JK

 

[vipzach]

Re: THE MATRIX EFFECT

calfsasaur, try that last prop that you have listed, the 17p.

 

[Alumarine]

Re: THE MATRIX EFFECT

yep, try the 17 and<br />please don't rev it so high in neutral

 

[Calfasaur]

Re: THE MATRIX EFFECT

Will check to see whats on the boat then see what happens. Well time for bed will revert soon many thanks for all your suggestions. Cheers C

 

[Wotknot]

Re: THE MATRIX EFFECT

If you rev it up in neutral to 4800 rpm, you're going to have more trouble than just too low rpm's.

 

[Alumarine]

Re: THE MATRIX EFFECT

Another thing, if the 17 is too small you may over rev it in gear.<br />Don't exceed 4800 rpm.