Mercruiser 470 Starter Solenoid replacement

[jtroendle]

Hi all,

due to starter problems i have decided to replace the starter and the separate solenoid by a new starter from sierra which combines also the solenoid.

After installing ( Batterie plus to big terminal, the yellow red wire to terminal S, the terminal marked with R is not connected) have now a strange condition,

When i try to start, the new soleniod starts to click but nothing happens. After furter investigations if figured to followig out, if i connect straight plus with the S terminal the starter cranks --> so solenoid is ok. If i switch the key to the start position i will get also power, but maybe to less to start. A test light indicated power. so i started to connect direct from the ignition switch with a wire of 2,5 qmm to the S terminal and started to crank, and this works:

Does anybody knows something similar to this , that based on the starter the current wiring is not big enough

Thanks for any feedback straight from Germany

regards

Juergen

 

[stonyloam]

Re: Mercruiser 470 Starter Solenoid replacement

OK you need to look at the wiring diagram in Mercruiser manual #8. There are TWO solenoids for the starter. When you turn the key to start it activates the slave solenoid bolted to the block, that in turn activates the solenoid on the starter. Are you sure which one is clicking? Go back there and listen when someone hits the start key. If the slave is clicking but not the starter, we can work on it from there. Sounds like the slave solenoid may be the problem.

 

[T-Max]

Re: Mercruiser 470 Starter Solenoid replacement

OK you need to look at the wiring diagram in Mercruiser manual #8. There are TWO solenoids for the starter. When you turn the key to start it activates the slave solenoid bolted to the block, that in turn activates the solenoid on the starter. Are you sure which one is clicking? Go back there and listen when someone hits the start key. If the slave is clicking but not the starter, we can work on it from there. Sounds like the slave solenoid may be the problem.

Juergen -

I just passed this link along to another poster. I think you might be able to make use of it based on Terry's post to you, although this schematic obviously doesn't tell you which wire goes where. I think that #11 is the slave solenoid that Terry mentioned (Terry?). Assuming that it is, you could put your test light onto the output terminal of the slave solenoid and see if it lights when you turn the key (and hit the start button?) since it should then be passing the current on to the other solenoid and starter. If your test light doesn't light, that solenoid isn't passing the current on and is thus perhaps defective. Here's the link -

http://www.perfprotech.com/store/assembly/STARTER-MOTOR-AND-WIRING-HARNESS,908-10,84-98269A 9.aspx

Terry -

Not stalking you, just seem to be on the same wavelength since I'm now getting to taking my starter off (I hope). Am I correct that #11 is the slave solenoid?

 

[stonyloam]

Re: Mercruiser 470 Starter Solenoid replacement

11 is it. But there are two types of slave solenoids: Refer to the starting section (4A page 3) of Mercruiser manual #8 (470 engines). If you don't have it go to adults only , #9 and download it. Your 470 should I believe have the switch type slave solenoid. That is when the solenoid is activated it sends battery voltage directly to the coil during starting. When you find the slave look for a purple/yellow wire going directly from a small terminal to the + side of the coil. You should have r/y wire going to the starter solenoid, provides voltage to starter solenoid for start. There is a starter troubleshooting sticky in the technical section at the start of this forum.

 

[jtroendle]

Re: Mercruiser 470 Starter Solenoid replacement

Hi all,

wow impressive the feedback in this forum after a short time. I have done some furter inverstigations.

To clarify further my target was initially to replace the old solenoid AND the starter by the new one which combines both in one piece. And now i found out the following: If i just attacht to the S terminal the yellow/red wire, and start to crank, the new solenoid which directly sits on the starter gets just not enough Ampere, because if i replace the yellow red wire by a 2,5 qmm temporary wire and start to crank if starts easily. So my understanding is that the original design with the old solenoid which works in the switch mode, the wire would be enough just to release the power flow. But the new one requires more Ampere to release the solenoid.

Solution:
1. I install from the ignition key switch a new wire which is bigger.
2. Still use the old solenoid as a main switch first to control the S terminal power .

hopefully i am right with my toughts

regards

Juergen

 

[stonyloam]

Re: Mercruiser 470 Starter Solenoid replacement

You are supposed to have two solenoids. The slave solenoid on the engine block is supposed to supply the higher amperage to the starter solenoid. If you are going directly to the starter from the ignition switch, you could burn out the switch. The y/r wire from the ignition switch activates the slave solenoid and the slave sends high amperage through the larger y/r wire to the starter (same as your heavy wire). The slave also bypasses the resistance wire and provides battery voltage to the coil during starting (p/y) wire. If you don't use the slave solenoid you are asking for trouble down the road.

 

[jtroendle]

Re: Mercruiser 470 Starter Solenoid replacement

You are supposed to have two solenoids. The slave solenoid on the engine block is supposed to supply the higher amperage to the starter solenoid. If you are going directly to the starter from the ignition switch, you could burn out the switch. The y/r wire from the ignition switch activates the slave solenoid and the slave sends high amperage through the larger y/r wire to the starter (same as your heavy wire). The slave also bypasses the resistance wire and provides battery voltage to the coil during starting (p/y) wire. If you don't use the slave solenoid you are asking for trouble down the road.

Hi Terry,

thanks for your feedback, this topic took me 2 evenings to get the know how but i still love this engine, and to run a new one is just boring enough.

Thanks to all for your help.

regards

Juergen