Concave hull / Low RPM

Discussion in 'Powerboats' started by BigD, Jun 7, 2005.

  1. mackid068
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    mackid068 Semi-Newbie Posts Often

    Is that the issue with the hybrid-electrics that Toyota's having?
     
  2. cyclops
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    cyclops Senior Member

    I have no knowledge of them.
     
  3. mackid068
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    mackid068 Semi-Newbie Posts Often

    Allrightey then. Just wondering. But in regards to the thread, how's the engine diagnostic process coming? And how is the hull-repair business going along?
     
  4. BigD
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    BigD Junior Member

    I installed new plugs, wires, coil, filter and tapped a fuel pressure guage into the line just before the carb. Ran compression test and checked timing. Ran the boat on the lake today and it ran very nicely. I gained about 100 rpm at WOT.

    The compression showed all cylinders within 5 psi of 100. Greatest separation was 10 psi. I saw a document on another post that showed this engine as having 150 - 160 psi compression. Maybe last owner threw on different heads along with the 1979 Q-Jet.

    Fuel pressure stayed around 5 psi from idle to WOT. About the only thing left before I start popping intake manifold and heads is the Quadra Jet. I think I've got about all I'm going to get out of this mixed up engine. I'll settle for now with the 17 pitch prop and 4200 rpm. Boat cruises pretty nice around 34 MPH and 3500 rpm.
     
  5. stevel
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    stevel Lost at sea

    The 100 PSI matches automotive history nicely with the circa 1979 carb. I'm thinking that the engine came out of a car or truck of that era. I'm used to seeing 110psi and lower readings for that era smallblock. My '81 big-block is 100-105psi All the way around.

    I really think your boat is doing well with that engine. If you want to mess with the bottom at a later date, I'll be happy to detail that procedure for you also. A body man who works on 'vettes would probably have the skill for the patching, but I'm not sure he'd have the facilities to flip the hull.
     
  6. mackid068
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    mackid068 Semi-Newbie Posts Often

    Flipping the hull could be done as can getting the fiberglass fixed. You just need time, money and a few telephone books.
     
  7. BigD
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    BigD Junior Member

    Thanks ..... I think the hull can wait. The problem with the engine is the 1987 block ID#. That's been the problem all along. I keep finding mismatched engine parts and accessories. I still don't know what distributer I've got. Gold top and cap with two screws holding down the cap, points and condensor. Prestolite? Mallory? GM?
     
  8. BigD
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    BigD Junior Member

    Back to the 1989 reinell 215c OMC350 260 HP.

    I've been able to coax 4300rpm at 38mph out of this engine with a 17 pitch prop and a bit of a tailwind. It is bogging badly at WOT and dropping rpm and speed. I'm told by Reinell dealers that I should be able to spin a 19 or 21 pitch prop at this rpm and thus attain higher mph. All engine #'s trace to a 1988 block, heads etc. The only problem I have found is the low compression across all cylinders (100 vs 150 list) I have not fiddled with the carb as yet. Kinda wondering what the bogging and loss of rpm/mph is at WOT. The boat is running acceptably at about 30 mph cruise, just the bog at 38mph WOT.

    Think I should leave it alone or start pulling heads and looking at gaskets and piston domes (or concaves as the case may be)??

    BigD
     

  9. mackid068
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    mackid068 Semi-Newbie Posts Often

    Good going! Sounds good. The engine is best left alone, probably. Go for a new prop, bottom cleaning, fresh oil and whatnot and then move on to the hull, see if you can fix that part up, maybe it'll bring your speed up a few mph (maybe 3-8 mph?)
     
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