'65 Merc 90 hp distributor problems

CoronaJeeper

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Jul 4, 2004
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I've got a Merc 90HP inline 6 that was running fine, then the distributor cap came loose and fell off while running, breaking the cap and snapping the dist. timing/drive belt. If I hold the dist. drive pulley, the rotor seems to have some play in it. Is this normal? It will turn about 30-40 degrees. That doesn't seem right. Is the entire distributor hosed? :( Also, while I was taking the various motor covers off to see how to replace this belt, I noticed the flywheel and the shaft that it bolts to is "wobbly". At first I thought the friggin' crank had broken, :eek: but I pulled the plugs to see that all six pistons move with the rotation of the crank. What the? Any old-school Merc guys have any ideas?
 

CoronaJeeper

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Re: '65 Merc 90 hp distributor problems

Anyone? Bueller? Bueller? Should I use this motor as an anchor?
 

briannh1234

Petty Officer 1st Class
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May 19, 2003
Messages
233
Re: '65 Merc 90 hp distributor problems

Sounds broke to me. There should not be any play in the distributor. As long as the mount for the distributor assembly is still in good shape than you may just need a new assembly. This would be a good time to do a compression check to make sure nothing else critical is broken.<br /><br />You may also want to look at the end bearing on the crankshaft - The only way to check it that I know of is to disassemble the whole block.<br /><br />I'm not sure which years distributors will fit your motor. Maybe some else here would know. <br /><br />I don't recommend using it as an anchor - you can sell it for more than the cost of a new anchor.<br /><br />Good luck.
 

emckelvy

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Jan 16, 2004
Messages
2,506
Re: '65 Merc 90 hp distributor problems

The old inline 6 dual-point distributors do have some play built into them, it's a hold-over from the direct reversing (Dockbuster) motors.<br /><br />You'll have to remove the flywheel in order to replace the distributor belt, at that time you can check the flywheel for problems. The play you feel may be a cracked or broken flywheel flex plate.<br /><br />Also, it's not unknown for a crankshaft to break, however it'd make a lot of noise. <br /><br />I'm still trying to figure out how all the dist. cap screws fell out, they've got locking tabs on them!!!!!<br /><br />Did it also break the coil contact coming thru the side of the cap? If so you'd need to add that to your parts list.<br /><br />Be sure you use a proper puller to remove the flywheel and DON'T take all the flywheel bolts out. If you don't have the factory-style puller that works off the threads in the flywheel center, use a good-quality harmonic balancer puller and remove two opposite bolts on the flywheel hub. Use these holes for the puller's bolts. When you reinstall the flywhel bolts be, sure to put a drop of Loctite on each and torque to specs.<br /><br />Here's a good section on timing and alignment that you'll need to utilize:<br /><br /> http://www.maxrules.com/timingindex.html <br /><br />HTH............ed
 

real550A

Cadet
Joined
Jul 10, 2004
Messages
18
Re: '65 Merc 90 hp distributor problems

Be careful!<br />I had a '57 Mark 30 that had the "loose feel" to the flywheel. It ran pretty good, but had a broken crankshaft!
 

Clams Canino

Commander
Joined
Jan 10, 2004
Messages
2,179
Re: '65 Merc 90 hp distributor problems

Flywheel play could just be the flex-plate doing what it does.<br /><br />If it was running fine before it broke - fix just what broke 1st. Those duel-point distributor assemblies are pretty common. Check John's Old Mercury board - or Ebay - the 80/85/90/100 between 1961 and 1965 all used that same distributor setup.<br /><br />-W
 

Clams Canino

Commander
Joined
Jan 10, 2004
Messages
2,179
Re: '65 Merc 90 hp distributor problems

See Ebay item # 2484176250 - That's your ticket.<br /><br />-W (not selling it - watching it)
 

CoronaJeeper

Recruit
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Jul 4, 2004
Messages
3
Re: '65 Merc 90 hp distributor problems

What is the flexplate? Is the flywheel not firmly fixed to the crank?? Dang it, if this was a smallblock Chevy, I'd have it running by now...
 
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