1970 40hp johnson

[first old boat]

I have a 1970 40hp johnson outboard engine I purchased a new marine battery and it will only turn the engine over maybe three revolutions and thats it if i take the plugs out it will turn over all day do i have something in my exhaust and if so how do i check it even with one plug out i get the same results thank you

 

[F_R]

Re: 1970 40hp johnson

It isn't the exhaust. You either have a weak starter motor, or bad cables, or bad connections. Do a voltage drop test on the cables, and connections and if Ok, it's starter time.

EDIT: You do a voltage drop test by connecting the leads of a voltmeter across each component or connection. Sould be zero volts across connections and very low voltage across cables. If you find a point with like say 4 volts for instance, say A-HA!

 

[tashasdaddy]

Re: 1970 40hp johnson

90% of starter problems are bad connections. remove and clean both ends of the battery cables, so that they are shiney, also the cable from the solenoid to starter. check for nicks in the cables. and make sure the connectors are on the wire good. the cable tend to corrode from the inside out, if nicked, corroded wires, and connections, heat up and cause resistance to the follow of electricity, thus the starter doesn't get enough. you can also take jumper cable pos battery post to large post on starter. with a good connection, the engine should spin. then if the starter is good clean everything and retest. then trouble shoot solenoid. starters can be rebuit at a starter/alternator shop, much cheaper than a new one.

also have the battery load tested at the auto parts store, free, i've had new batteries go bad