omc 5 liter will not rev past 2,000 rpm

Second Mate

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background: Four Winns 205 sun-dancer boat sat for 8 years. would not start. Motor has 122 hours on hour meter (meter works). installed new points (dwell at 30 timing set at 8 degrees and advances with acceleration) condenser, rotor, cap, wires and coil. motor starts but does not rev. replaced fuel filter. rebuilt carburetor with new filter at carb, running with clear line out of external tank with new fuel. no bubbles or fuel leaks. same problem. did compression test, all cylinders 175 to 180 psi. bypassed esa switch, same problem. replaced fuel pump (old pump tested at 5 psi at carb, new pump is at 6 psi). engine purrs like a kitten at an idle (550 rpm). it will accelerate to around 2,000 rpm with no problem. any after that and she bogs down and pops thru carb. I pulled the distributor plate and checked the counter weights, all moving no problems. I checked for excessive play in timing chain by removing all plugs and moving crank by hand and watching rotor. crank only moves about a quarter of an inch from clockwise to counterclockwise with rotor movement. I checked for leaks at intake manifold and carburetor. I have triple checked all wiring from distributor to plugs. I am at a loss. anyone have something that I have not already tried? thanks in advance for any assistance.
 

Don S

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Re: omc 5 liter will not rev past 2,000 rpm

With the dwell meter hooked up and in neutral raise the rpm up to 2000 rpm and see what the dwell does. Does it stay at 30?
 

Second Mate

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Re: omc 5 liter will not rev past 2,000 rpm

no the dwell decreases. the higher the rpm the lower the dwell goes. I always thought that dwell would remain constant and the timing would change.
 

Second Mate

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Re: omc 5 liter will not rev past 2,000 rpm

as an update, I just got in from removing the exhaust boots to check the flappers. both intact and working. I thought I might get lucky...GROAN.
 

Don S

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Re: omc 5 liter will not rev past 2,000 rpm

no the dwell decreases. the higher the rpm the lower the dwell goes. I always thought that dwell would remain constant and the timing would change.

You'r right, it should.

Sounds to me like you forgot to install the c or J shaped spring that goes on the points to push them closed.
The points are floating at higher rpm and not opening and closing.

Here is a picture I found of a set of points with the spring in the upper right.

3032809_bwd_a124h_pri_larg.jpg
 
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Second Mate

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Jun 25, 2011
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Re: omc 5 liter will not rev past 2,000 rpm

Don,
You have saved my 4th of July weekend on Lake Erie. it was a stupid mistake that I made, I had the spring on the points but not in the correct way. they were just going along for the ride. I have about 20 hours invested over the past two weeks and that is bad. The silver lining in all this is that just this morning the water pump failed (water squirting out the little hole in the back) and just now when I installed the points and gave her a goose, the water pump belt broke and took out the power steering belt. I would have been 10 miles out on Lake Erie without cooling had I not made the mistake. Thank you very much for your assistance and for the quick reply to my SOS.
 
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