85 Johnson 70HP won’t turn over

Mtneer

Cadet
Joined
Aug 4, 2009
Messages
22
Picked this boat up recently - 70HP Jihnson.

battery is dead but I hooked it to a boost pack and it just slow cranks.

connected it to my buddies tow truck with jumper cables - same result.

Unlikely a battery issue right?
 

oldboat1

Fleet Admiral
Joined
Apr 3, 2002
Messages
9,612
Briefly connect jumpers direct to starter to see if the starter has issues.
 

Mtneer

Cadet
Joined
Aug 4, 2009
Messages
22
If I out to the pack directly on the starter the starter seems to fire as normal
 

jakedaawg

Rear Admiral
Joined
Jun 26, 2012
Messages
4,275
Clean all battery connections. Engine side, and battery side. Get good battery. No wing nuts. Use a wrench. Ohm battery cables, they do not last forever. Solenoids go bad as well.
 

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,847
redo to a shiny state all connections incl those on the starter selenoid !! could be just oxydation inside cripped connectors
 

Mtneer

Cadet
Joined
Aug 4, 2009
Messages
22
Ok the back beat goes on... thanks guys

it it was a battery issue- for a new battery and it start and runs...

NEW PROBLEM

It idles fine high and low - goes into gear and runs well ... even heads toward top speed and gets really going and then does out.

after that it runs on low speed ok but when I try to go full throttle forward it wants to choke out and die.

we had a dry rotted field hose from where the couple meets the motor to the fuel pump(?). And we replaced it with a piece Of hose from the fuel line with the pump bulb.

hopenthis made sense - thanks in advance
 

fireman57

Captain
Joined
Aug 24, 2004
Messages
3,811
When it starts to die push the key in and let the primer shoot a little fuel in it and see if it takes off. If it does it's probably time to go through the carb. You can also have a buddy pump the primer bulb and see if it picks up. If it does then you have a weak/bad fuel pump.
 
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