mercruiser 170 wont stop cranking

[boattoy]

when I went to try to crank over the motor and i got nothing. found out the slave solenoid was bad. bought a brand new one and it started cranking again. BUT something weird started to happen. When i crank the motor it would continue to crank for a second or two after i release the key(ignition is new).

the starter is new as well. So i disconnected the positive leads from starter, and when i turn the key, both the slave and the starter solenoid work fine(they click on/off right when i turn/ release the key). i connect the + back up, turn the key and now it just keeps cranking unless i disconnect they battery. One thing i did notice is that it cranks a little faster when i rotate the key to the start position. One thing im not 100% sure on, is there are two posts on the starter solonoid to connect the slave solonoid lead. what is one or the other for? My older starter one is labeled R and other is S.

 

[Trunks]

Re: mercruiser 170 wont stop cranking

i had the same problem .... all i did was actuate the solenoid a few times to break it in ... so cranked it and when it jammed i took my rench and hit the solenoid ... couple times and it will stop

 

[GMC2003]

Re: mercruiser 170 wont stop cranking

Did the same as Trunks, hit it a couple of times with the handle of a screw driver and it stopped.

 

[dirtdog38]

Re: mercruiser 170 wont stop cranking

oneworks the soilnoid the other is a acc or a exciter make sure your not sending power to one of the little ones all the time u dont want 12 volts to the post untill u hit it u can take them off the starter and jump across to crank it 2 thats how i start somthing with no key really id just cut it long and touch it to power to turn them over

 

[Don S]

Re: mercruiser 170 wont stop cranking

Did you install the right kind of slave solenoid????
This sounds real familiar, read this thread and you will see why.
http://forums.iboats.com/showthread.php?t=491992

 

[boattoy]

Re: mercruiser 170 wont stop cranking

i got a ford fender mount slave solenoid. the markings and mount are identical (new and old). They both have I and S marked on the two front posts. why do these slave solenoids need two inputs? it works with just the starter wire from ignition switch hooked up

I tried to "break in" the solenoids by disconnecting power to starter but not to both the solenoids. they both click on and off instantly with the key(did it a bunch of times with zero issues). the old solenoid and starter never did this. should i try moving wire from slave to other post on the starter's solenoid? are one of them supposed to be grounded? none of the wires are hacked up so i know im not missing something

 

[Pete104]

Re: mercruiser 170 wont stop cranking

Try taking the "I" wire off while your installing it. That post energizes the ignition while cranking. If it starts without it cold, problem solved. Had this a couple times. I think the purchasers don't know what they buying. Older parts listings are specific on heavy duty or not.

 

[boattoy]

Re: mercruiser 170 wont stop cranking

here is a pic of what i got...

if it does work, why would the boat be wired to use the "I" post then?

 

[Pete104]

Re: mercruiser 170 wont stop cranking

Parts back then were engineered for these oddities that simple electronics nowadays can't.

 

[boattoy]

Re: mercruiser 170 wont stop cranking

I disconnected the ignition wire and it still kept cranking. I even beat the crap out of the solenoid and that didnt stop it either. I guess ill try bolting old starter in tomorrow since it wont cost me anything

 

[Fishermark]

Re: mercruiser 170 wont stop cranking

Solenoids don't require "breaking in" or any other such thing. You either have a faulty solenoid, or it's wired wrong, or it's the wrong one. Why buy a Ford fender mounted solenoid anyway? Why not buy the right slave solenoid? Why try to re-invent the wheel when the right part is cheap and plentiful?

 

[Bt Doctur]

Re: mercruiser 170 wont stop cranking

Why do some have "S" ,"R", or "I"
S: solenoid trip lead, this is what pulls the plunger in
R,I : used to supply full battery voltage when cranking
Most non marine used the grounded base(Ford type) meaning the metal base needs to be grounded to operate.Marine units need a ground supplied to make it operate. using the wrong type can activate the solenoid similiar to the relay used on a car alarm. Once activated you need to remove the power supplied to reset the relay.Typically due to the small gauge wiring in boats a slave solenoid is used to operate the main solenoid on the starter.

 

[Don S]

Re: mercruiser 170 wont stop cranking

Since it's impossible to see the wire colors going to the solenoid, or where the wires go to, the picture really doesn't help much.
Also can't tell which is the I or S terminal on the solenoid.
Using your picture, here is how it should be wired.

 

[boattoy]

Re: mercruiser 170 wont stop cranking

sorry about that... just realized that pic did suck for wiring reference. I have it wired the way you said and NO those wires arent close enough to arc or touch. only difference is my "S" wire is white with green strip then goes through the neutral safety switch and then its white/red. Ive tested the wires. the "I" gets voltage when key on and "S" gets voltage with key turned to start position. so my boat isnt wired to ground the solenoids. whats weird is it got progressively worse as i started to try messing with it. it went from barley running, after i release the key, to non stop.

can the solenoid on the starter maybe hang up when under a load and maybe causing it to continue to run? could is maybe just need grease?

i have no problem buying the correct slave solenoid if nothing else works. I just didnt know there are differences.

 

[dirtdog38]

Re: mercruiser 170 wont stop cranking

yes the ford kind you have ther do it alot more than the other kind.seems like a low battery when trying to start or alot of cranking will make them do that. seen it alot on fords in the junkyard. growed up in one dad had it 40 years or more

 

[Bt Doctur]

Re: mercruiser 170 wont stop cranking

Theres your answer, your powering the solenoid with the key on. Anything "hot" with the key on powers something, coil, gauges, etc. The only time the solenoid should see power is with the key on "start" .Removing the "I" wire should cure the run on.

 

[Bt Doctur]

Re: mercruiser 170 wont stop cranking

Somewhat generic, but you should see what we saying
http://www.boatfix.com/merc/Techbk/94/94hg4a.pdf
page 4A-3

 

[Don S]

Re: mercruiser 170 wont stop cranking

I have it wired the way you said

No you don't, you have the wrong color wires hooked up.

only difference is my "S" wire is white with green strip then goes through the neutral safety switch and then its white/red.

Now, I'm really confused. There shouldn't even be a white/red wire in you wires, second, the white green wire should go to the shift shift interrupt switch (not a neutral safety switch).

The solenoid grounds through the base, and you do have the proper solenoid for your application.

Here is the correct wiring diagram for your 470.
http://forums.iboats.com/attachment.php?attachmentid=101093&stc=1&d=1309627110

 

[boattoy]

Re: mercruiser 170 wont stop cranking

here a better pic... the only yellow/red wire is the short wire from solenoid to starter.

I pulled the starter and bench tested it. it turned on and off fine.

i already tried to disconnect the I terminal. No change

what is the part number for the correct slave i need? Gonna see if local marina has one in stock

 

[Don S]

Re: mercruiser 170 wont stop cranking

I have no idea where the white/red wire comes from. You might try stripping back some of the tape in the harness and make sure of the color. It could be faded you yellow. Did you look at the wiring diagram I posted?
I also don't see that the white green wire is hooked to the start system in any way.