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58 Evinrude BigTwin

bill_w

bill_w

Advanced Contributor
Finally got my 35 hp on a boat. This has been gone over from ignition (all new) to gearcase (all resealed). It runs great at high speed, but at idle to just over the 'Start' position on the tiller, it makes a loud 'clanking' noise. It sounds like the powerhead is going to blow up. Its not a steady noise, but happens every so often. Almost sounds like the flywheel is hitting a coil, but its not (I checked). Doesn't matter if its in gear or not, its there. It doesn't sound like piston slap, bad rod bearing, or any other noise I'm familiar with. Just the sound of metal hitting metal. Anyone have any ideas? The noise is coming from the powerhead as far as I can tell.
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Does it do it with the cover removed??? Could it be in the recoil start assembly??? You could remove it and rope start it to check. Try retorquing the Flywheel nut.
 
Yup, does it with the cover off. I can pull the recoil off and try that..don't have to rope start it, it's electric. In fact, doubt if I could rope start it. This thing is a bear to pull over, that's why I installed a starter. I'll try this weekend.
 
Does the shifter temporarily jump out of gear when this occurs? A clutch dog is a common problem with these motors.
 
Nope, not in recoil starter. Nope, doesn't jump out of gear, or into gear. Its getting worse. Still runs great at high speed, but at idle or just above, its banging so bad the whole motor jerks in the direction of rotation. I'm thinking it might be a bad rod or crank bearing, seizing or sticking once in a while. I pulled the motor off the boat, I don't want to blow it. I guess I may have to tear down the powerhead, unless anyone has any more suggestions??? Oh yeah, I checked the speed with a GPS...28mph wide open..got a 77 20 merc on it now...that does 26mph.
 
Before you start taking the powerhead apart, pull the flywheel and look for any sign of damage under there.
 
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