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.Boat: '91 Rinker Captiva 18'-6 (about 3000lb loaded) w/ '91 4.3 Mercruiser & 3 blade 17" pitch SS prop.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??? I don't believe it would be worth the trouble and expense to convert to EFI.I know, the real answer is V8 powered ski boat, wife wants pontoon, so we compromise & keep existing boat.Thanks

[lorax]

I've got the same boat and motor but older '89. I'm pretty sure that's a Merc Thunderbolt ignition (no points)I thought this thread had some interesting ideas in it... http://forums.hotboat.net/ubb/ultima...=000651#000000

[Capt. T]

IORAX- What kind of performance do you get?

[andrewgroup]

I have a 1990 Mariah 1850XL With OMC 4.3L Cobra Outdrive.Here is what I did to improve low end..4500 RPM WOT / 19" 14-3/4 3 Blade Aluminum PropI was getting 45 MPH with this but coming on plane and holeshot was not so great.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)I also installed a StingRay Whale Tale on the Outdrive. (39.00 from West on sale)This made a huge difference with the boat,4500 WOT is now 41 MPH, but getting on plane and having power during the holeshot has improved greatly.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]

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.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]

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.V/RJohn

[P.V.]

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]

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]

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

[Bond-o]

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.......