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66 Evinrude Sportfour WOT problems

M

Mikka8701

Contributing Member
Hi All,

so so I took my boat out over the weekend for the first time and it seems that under Wide open throttle the boat Rpms won't move past 4000 or 4500 and is almost stuck there. It occasionally would move to around 6000 if I was running WOT for approx 5 minutes. My questions is what is the maximum rpms this engine will run at to achieve maximum speed? And does anyone know why it wouldn't be going past the 4500 rpm
range?

model is 1966 evinrude Sportfour 60652
 
Scratch a mark across the prop and the prop hub. Take it and run it until it seems to slip and check the marks. If they are out of alignment, the hub was slipping.
 
Boobie said:
Scratch a mark across the prop and the prop hub. Take it and run it until it seems to slip and check the marks. If they are out of alignment, the hub was slipping.
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I checked the prop it seems fine however when I wot I can hear the engine backfiring could it have something to do with the timing ? I changed the timing and can either get it to run smooth on idle and **** on high rpms or really rough on idle a great on high rpm
 
Are you sure it is backfiring at WOT???? That would be so very unlikely. What would be likely though, is a worn clutch dog causing it to come out of gear, rotate one-half revolution, and slamming back into gear. You will feel a jolt as if you hit something.

If that is what you have, the lower unit gearcase has to come apart to fix it. Don't delay on this, every time it bangs, it causes more damage, including to other parts.

As others have said, 4000-4500 is correct, and the motor would appear to be OK on that score. A jump to 6000 probably is due to cavitation or ventilation (air around the prop)
 
Boobie said:
The timing only goes one way on that motor.
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The storage thing is when I time it correctly it doesn't start or runs portly at idle evan when adjusting the slow speed idle needles correctly. I just don't get it and am fed up with it. Originally everyone said that the engine was too fast for my boat but I definetly don't feel that way and yes it does pop under wot
 
Whatever you say. But I have to tell you I've never heard of one backfiring at WOT. I suppose it could be possible if the distributor cap is cracked or carbon tracked or something. But I've heard of tons of them banging at speed because of the worn clutch dog.
 
I think it is time to buy a new big $$$$ motor.---------New motors are just wonderful and start with just a turn of the key.---Computor does all the thinking for you.
 
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