Will not turn over with all plugs on.

[Seniornewboater]

NEED HELP !!!
I am new to marine outboard.
First time I completely rebuilding a 1982 70hp Johnson outboard. I am quite good experienced with car engine and transmission rebuild though.
After careful put thing together, I have problem with cranking the motor.
The motor turns freely with no plug, or any two plugs, but is unable to turn with all three plugs (please see attached videos).
Old starter, starter from a running motor, even a brand new starter, ...same thing.
What am I missing, or did something incorrectly to the internal components,...
I am dumbfounded, and run out of idea.
Your suggestion is very, very appreciated.
Best regards.
Seniornewboater

 

[ct1762@gmail.com]

load test the battery and clean all connections. if that still doesnt do it, rebuild the starter with new brushes. should fix you right up. also verify the starter mounting bolts are torqued to 130 in/lbs and not moving.

 

[Seniornewboater]

Hi Chief Petty Officer,
Thank you for your prompt reply. But starters, batteries, electrical connections were carefully inspect, check, and swap many times still make no difference.
I attached the videos, but do not see them in the post.
May I send the videos to your mail address?
Regards

 

[ct1762@gmail.com]

is once cylinder hitting the spark plug? did you align all the dowl pins in the crank? if the center split bearing is off, it wont seat right and hang up on the crank case as well.

 

[Seniornewboater]

I did disassemble and recheck crank shaft, main bearing, rod bearing, and check for sign of piston hitting the plug,... but nothing suspected.
Dowel pins for the main bearing were properly seated, aligned.

 

[racerone]

How did you line up the connecting rod caps ?----What method did you use to verify perfect alignment ?

 

[Seniornewboater]

Hi Racer one,
By eye. I connect rods to shaft one by one, turn shaft while tying the cap, making sure there's no friction, or any change to the shaft until cap bolts torque to specs.
I follow Seloc book instructions, but use my common sense when rebuild the motor.
Could you explain more for the critical of the rod cap alignment.
Regards

 

[racerone]

These rods are ----CRACKED-----As part of the manufacturing process.----The cap only fits one rod and one way ( dots ) on one side.-----So the surface is irregular.----You assemble these carefully making sure the edges line up.----I use a pencil lead to see if it catches at all.

 

[Seniornewboater]

Yes, they are go together, there's no mixing of the rods or caps. They are carefully marked as pair before disassemble.
What else could you think of that cause the problem?

 

[RBoyd1971]

How old are your battery cables and what gage are they. Remove them and check the resistance with an ohm meter. I had one doing that recently and once I put new fine strand marine cables on it it'll turn over with almost no resistance. I cut the old ones open and some of the copper had turned to red dust. You could try some good jumper cables and see if that makes a difference. Just don't use the cheap ones that are copper clad or you'll get the same thing
.

 

[RBoyd1971]

Oh, and don't use a deep cycle battery on it. Use a cranking battery.

 

[Faztbullet]

Replace the solenoid

 

[Seniornewboater]

Thank you RBoyd1971 and Faztbulet,
I have already tried car jumper cable direct from battery to starter, bypass starting circuitry, but make no difference.