1991 4.3 L Mercruiser

[Capt. T]

Boating season in WI is just about over (early out for me this year) and I'm thinking about what I can do to get better performance e.g. holeshot, out of my boat next year. Kids are getting bigger and will be learning to ski & tube in the next couple of years. Right now with 5 people (adults & kids) it seems to take forever to get up on plane.<br /><br />Boat: '91 Rinker Captiva 18'-6 (about 3000lb loaded) w/ '91 4.3 Mercruiser & 3 blade 17" pitch SS prop.<br /><br />I think this engine has points e.g. no electronic ignition. Am I right? Would it be worth converting to electronic ignition? Is so how? Pertronix???<br /> <br />I don't believe it would be worth the trouble and expense to convert to EFI.<br /><br />I know, the real answer is V8 powered ski boat, wife wants pontoon, so we compromise & keep existing boat.<br /><br />Thanks

 

[lorax]

Re: 1991 4.3 L Mercruiser

I've got the same boat and motor but older '89. I'm pretty sure that's a Merc Thunderbolt ignition (no points)<br />I thought this thread had some interesting ideas in it... http://forums.hotboat.net/ubb/ultimatebb.php?ubb=get_topic;f=2;t=000651#000000

 

[Capt. T]

Re: 1991 4.3 L Mercruiser

IORAX- What kind of performance do you get?

 

[andrewgroup]

Re: 1991 4.3 L Mercruiser

I have a 1990 Mariah 1850XL With OMC 4.3L Cobra Outdrive.<br /><br />Here is what I did to improve low end..<br />4500 RPM WOT / 19" 14-3/4 3 Blade Aluminum Prop<br />I was getting 45 MPH with this but coming on plane and holeshot was not so great.<br /><br />I took the Prop to Precision Propeller, (This is the repair division of Turbo Prop here in Indianapolis) The Prop guy said to repitch to 18" and put a good cup on the blades. (75.00)<br /><br />I also installed a StingRay Whale Tale on the Outdrive. (39.00 from West on sale)<br /><br />This made a huge difference with the boat,<br />4500 WOT is now 41 MPH, but getting on plane and having power during the holeshot has improved greatly.<br /><br />Other will suggest a good stainless steel prop, 4 or 4 blade. I wouldn't consider this unless your boating in a swimming pool, but they sure add a lot to the bottom end.

 

[lorax]

Re: 1991 4.3 L Mercruiser

My '89 186 Captiva will do about 45 with two adults and a couple of small kids. We haven't done much sking but the boat seems to come out of the hole relatively quickly.<br />I'm using a 19 pitch stainless three blade prop and there is a "wale tail(?)" attached to the cavitation plate. The motor is a 4.3L two barrel.

 

[bluewater19]

Re: 1991 4.3 L Mercruiser

I have a 1991 bluewater 19' cuddy cab. 3500lbs.same mercruiser engine. I run a 21 pitch stock aluminum prop at 44 mph. This winter I put a 4bbl carb and manifold on it(check out ebay paid under 200 for mine). Before with the 2bbl it ran 38 mph. You might think about getting a highfive prop for your boat. I put one on mine for water sports. The reason I did all this is I am 250lbs and getting out of the hole was a problem when I was sking. Now the thing will pull my arms off!I used a 19 pitch highfive for my application. The top speed is down to 40 with the highfive. Also the thunderbolt IV ignition is electronic check out the module on the port riser.<br />V/R<br />John

 

[P.V.]

Re: 1991 4.3 L Mercruiser

Order up a High Five Merc prop. Play with the vent holes. You won't get better performance for sking ,for the dollar!! Don't screw around with anything else, unless you have lots of $$$ and lots of time/patience !!!

 

[Capt. T]

Re: 1991 4.3 L Mercruiser

Thanks all for the advice. Looks like I'll be saving up for a High Five for water sports and maybe back off to a 15" pitch 3 blade alum. for river running e.g. cheap.

 

[ronclement20]

Re: 1991 4.3 L Mercruiser

I have the same set up 4.3 thunderbolt electronic ign 18 ft glastron alpha one gen2 and with a 17 pitch my hole shot jumps out of the water faster than any outboard ive ever had top spd 38mph with a 19 pitch its a little slower but still impressive and i get 55 mph top spd i think you just need a good tune up 4.3 is as powerful as v8 torqe wise

 

[Bondo]

Re: 1991 4.3 L Mercruiser

September 15th, 2003, 06:03 AM

Ayuh,.... Welcome Aboard ronclement20,....
I'm guessin' maybe Santa fixed up Capt.T for Christmas,.... Probably a few Years ago....
The archives are for Learnin',..... Not postin' answers to.......