Re: Newly rebuilt 1986 350 OMC Overheating at WOT
Thank you Dakota47!!
I replaced the impeller, which looked perfectly fine all around. I installed the full kit with housing as well. The overheating is solved!! Thank you Dakota47
Now its running good and not over heating, but now I realize I have an oil leak, looks like about 1/2 a quart in the bilge after a few hours of operation. I can't see where it's coming from. Boo.
Also, top speed is about 42 mph, measured by speedometer and by GPS. I really thought I would get closer to 55-60mph.
I've tried switching pitches, 17, 19 and a four blade 21. All top out about the same speed. The 17 over-revs a little, around 4800-4900. The 19 maxes at 4500-4600 and the 21 at 4200. The 17 feels best, quick out of the hole, responsive, engine not labored. I think an 18 would probably be perfect but I'm really surprised I'm not going faster. I presume its just the way it is, but if I can make it go fast I'd like to.
Better flowing heads and intake and through hull exhausts would add 30hp but I'm not spending that, at least not this year. Plus, if I spent the couple grand+ on that and I was maxing at 47mph after I'd think it was a complete waste. Now if I was suddenly able to hit 65-70mph, well at least then I'd get some grins for my bucks.
My boat is a 1986 Caribe 200. I've found references to the weight of the boat at 1700 dry, (seems light) and 3000 laden. It is a fiberglass shallow-V planing boat. The hull has some oxidation on the bottom, but it's kept on a trailer so there's no growth. I'm running in fresh water.
Change the IMPELLER , looks can be deceving. my 19 ft ski boat with omc 4.3 would run 175-180 degrees and last week i changed the Impeller ( looked new) i bought the complete kit ,Housing and all. i installed it and now she runs @ 160 all day long..
oh yea, check the power steering cooler for water flow.
