starter solenoid

DMETON

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Feb 16, 2022
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5
I just bought a 1972 Evinrude 25hp outboard. The starter wouldn't turn over with the switch. The switch checks out to be good and I can start the motor when I jump the two large terminals on the solenoid. I figured the solenoid must be bad so I ordered a new solenoid and installed it the same way the old one was wired. It still won't start with the switch. Is there a fuse somewhere that I'm missing or did I get a bad solenoid?
 

Crosbyman

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Nov 5, 2006
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5,796
see diagram not complex battery +12 must reach the switch "Batt" (GREEN) and turning the key puts +12 on S...(tan) . it must reach the selenoid to activate so just follow the +12 to the switch and back to the selenoid check the fuse if you have one ... diag. shows none :) clean all contact points in case oxydized or bad

1648220838795.png
 

kbait

Commander
Joined
Nov 13, 2007
Messages
2,475
One of the small terminals on solenoid gets 12v when switch is in start position. Other small terminal must be grounded to block for solenoid to operate. That ground may go through a neutral safety switch (follow wire..on opposite side of powerhead). That switch may be faulty/out of adjustment.. you can just ground that wire, but starter will engage in all gear settings.
Good luck!
 

DMETON

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Feb 16, 2022
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5
see diagram not complex battery +12 must reach the switch "Batt" (GREEN) and turning the key puts +12 on S...(tan) . it must reach the selenoid to activate so just follow the +12 to the switch and back to the selenoid check the fuse if you have one ... diag. shows none :) clean all contact points in case oxydized or bad

View attachment 357734
This drawing looks like what I've got, excluding the electric choke. I also checked the old solenoid by jumping the 3/8" terminals to a battery and it clicked. I'm thinking that I didn't need a new solenoid and must have a short somewhere or a bad ground.
 

Crosbyman

Vice Admiral
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Nov 5, 2006
Messages
5,796
what you likley have is a broken wire or defective start key.
if yourengine does have a safety interrupt along the wires controlling the selenoid then you must test hit for continuity when in NEUTRAL

parts diagram shows a wire to a safety switch via a small wire off the selenoid...

some safety features will interupt the GRD for the selenoid if so eqpt'd

you need to probe the key and should have +12 on BATT then it must transfer to S when the key is turned... then it must reach the selenoid


at the very least turn and hold the key on START then wiggle shake prod all the wiring. if you get a starter reaction you found the problem .


in conclusion you need to track down the +12v if does not reach the selenoid whatever the reason. use a test lamp to ground or a VOM one side to grd.
 
Last edited:

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,821
??----The parts book for the electric start kit seems to show a safety switch.----If throttle is open too far it will not crank.----Look for it.----If it is there and does not work it may need to be cleaned.----Yes they are easy to take apart for cleaning !!
 

DMETON

Recruit
Joined
Feb 16, 2022
Messages
5
what you likley have is a broken wire or defective start key.
if yourengine does have a safety interrupt along the wires controlling the selenoid then you must test hit for continuity when in NEUTRAL

parts diagram shows a wire to a safety switch via a small wire off the selenoid...

some safety features will interupt the GRD for the selenoid if so eqpt'd

you need to probe the key and should have +12 on BATT then it must transfer to S when the key is turned... then it must reach the selenoid


at the very least turn and hold the key on START then wiggle shake prod all the wiring. if you get a starter reaction you found the problem .


in conclusion you need to track down the +12v if does not reach the selenoid whatever the reason. use a test lamp to ground or a VOM one side to grd.
 

DMETON

Recruit
Joined
Feb 16, 2022
Messages
5
Found it! Had a bad ground from solenoid to block. I built a new ground wire and routed it straight to a mounting screw. Thank you!
 

DMETON

Recruit
Joined
Feb 16, 2022
Messages
5
what you likley have is a broken wire or defective start key.
if yourengine does have a safety interrupt along the wires controlling the selenoid then you must test hit for continuity when in NEUTRAL

parts diagram shows a wire to a safety switch via a small wire off the selenoid...

some safety features will interupt the GRD for the selenoid if so eqpt'd

you need to probe the key and should have +12 on BATT then it must transfer to S when the key is turned... then it must reach the selenoid


at the very least turn and hold the key on START then wiggle shake prod all the wiring. if you get a starter reaction you found the problem .


in conclusion you need to track down the +12v if does not reach the selenoid whatever the reason. use a test lamp to ground or a VOM one side to grd.
I found that I wasn't grounded from the solenoid to the block. Thanks!
 
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