Sr2 starter motor problems

[BODs SR2]

When I press the start button I hear a click but no movement. After repeating this a few times normal operation occurs. Turnover seems strong with no starting problems. Battery is good. When I just get a click, if I don’t release the button quickly or press it again repeatedly without a few seconds break it can blow the 30A fuse. Any ideas please. 

Just to add it doesn’t always do this and engages first time. Problem has been there for ages just learned to live with it and have a bag of fuses to hand. 

[Tracy D'arth]

Check the wiring and connections from the starter button to the solenoid small terminal. Is the starter button up to the job? The solenoid draws quite a lot of current and if it fails to fully travel it will draw it for a longer time than normal, hence the fuse blowing.

I would suspect the button is not making a good contact, does it work 100% if you short it out?

Try making multiple fast stabs on the button, it may clean up the contacts a bit.

[bizzard]

Because of the heavy load on the these big starter motors I always use the old type stand alone starter solenoids on these engines as a relay switch to protect the starter switch or button. The type of solenoid as fitted to old cars, preferably one with a button which can when pressed also be used to start the engine without using the key or button starter.

[Arthur Marshall]

When this happened to me, it turned out to be a bad earth connection from the starter. Moved it somewhere else,  cleaned it up, and no more problems. Couldn't believe it was such a simple cure.

[john.k]

You probably have a CA45 starter........reliable starter,but can furr up the contacts if let sit for a long time.......they are quite complex inside ,even though they look simple.....

[bizzard]

8 minutes ago, john.k said:

You probably have a CA45 starter........reliable starter,but can furr up the contacts if let sit for a long time.......they are quite complex inside ,even though they look simple.....

I doubt it, those were usually used on the STW3, ST3, sometimes SR3.

[Tony Brooks]

1 hour ago, Tracy D'arth said:

The solenoid draws quite a lot of current and if it fails to fully travel it will draw it for a longer time than normal, hence the fuse blowing.

 

This is to the OP, not Tracy.

Actually it is a little more complicated than that. There are normally two coils in the solenoid. A pull in that draws a lot of current plus a hold in that draws far less. The pull in coils earths (runs to battery negative) through the starter than has all but zero resistance when stationary. As soon as the solenoid contact make they put 12V positive on the starter so the pull in coil now has 12V positive on both sides of it, which in effect turns the pull in coil off. That just leaves the low current hold in coil energized.

 

So, what does that tell us?  The fuse blows so the pull in coil is not turning off. That means either the solenoid contacts are dirty/burned, the starter is jammed and can't start spinning, or in rarer cases something in the solenoid operating circuit to or from the ignition switch is reducing the voltage and thus current flow at the solenoid so although it might pull in it does not make firm contact.

 

Edited to add: try shorting the main starter 12V plus terminal to the small solenoid terminal with just a single wire on it, be firm, expect a spark. If it works every time its the switch/circuit. If it is intermittent it is probably the solenoid contacts.

 

The fact that it will work as intended at times makes an actual, motor fault less likely. I would suggest that (as JK says) it is probably dirty contacts in the solenoid. They can be cleaned by the boater providing they have the means of soldering and de-soldering and ensure the plastic solenoid cap goes back on in exactly the same way it came off. If you rule that out it is probably a faulty start switch, loose/dirty terminals, or undersized cable. Sir Biz has one answer, an old car type stat solenoid.

 

PS I am sure those starters need their solenoid/pinion throw adjusting, especially if  a new solenoid is fitted so if you don't know   how to do it best not take the solenoid ff the motor but you can take the solenoid cap off without upsetting the adjustment. I have known the odd pinon end bracket nose knocked off by a maladjusted solenoid throw.

Edited April 18, 2022 by Tony Brooks

[bizzard]

One of these, new from AES, Auto Electrical Services, about £25  The rubber covered button can be used to start the engine. 

[BODs SR2]

Great thanks will get on to it. Let you know. 

[BODs SR2]

4 hours ago, bizzard said:

One of these, new from AES, Auto Electrical Services, about £25  The rubber covered button can be used to start the engine. 

Can’t find it have you a link. May as well upgrade to this anyway. Cheers. 

[bizzard]

1 hour ago, BODs SR2 said:

Can’t find it have you a link. May as well upgrade to this anyway. Cheers. 

Sorry, it's AES, Auto Electrical Supplies.

Edited April 18, 2022 by bizzard

[BODs SR2]

Great thanks will get on to it. Let you know. 

2 hours ago, bizzard said:

Sorry, it's AES, Auto Electrical Supplies.

Sorry still can’t see it. What’s it’s part name. 

[Tracy D'arth]

 

 

What are you going to do with another solenoid?

If the solenoid on the starter is not working properly, this extra one will do nothing. If it is just to replace your start button then fair enough.

Edited April 18, 2022 by Tracy D'arth

[springy]

AES link for 12V

 

https://www.autoelectricsupplies.co.uk/product/129

 

springy

Edited April 18, 2022 by springy
add 12V

[bizzard]

1 hour ago, Tracy D'arth said:

 

 

What are you going to do with another solenoid?

If the solenoid on the starter is not working properly, this extra one will do nothing. If it is just to replace your start button then fair enough.

To wire up and use as a relay, much lighter to work than the starters own solenoid straight from the starter key or button. Many old Listers use them as a relay.

[BODs SR2]

2 hours ago, Tracy D'arth said:

 

 

What are you going to do with another solenoid?

If the solenoid on the starter is not working properly, this extra one will do nothing. If it is just to replace your start button then fair enough.

That’s the idea Tracy May as well while I’m at it. Cheers. 

1 hour ago, springy said:

AES link for 12V

 

https://www.autoelectricsupplies.co.uk/product/129

 

springy

Cheers. Hitting the buy now button…..

[john.k]

Until the OP supplies an ID or pic for the starter ,only guesswork..........IMHO,solenoids such as the one pictured are only really needed for CA45 starters that take a lot of current to work the internal circuits..........Even a CA 45 will work for a long time with an ignition switch ,but sans solenoid as pictured,the internal contacts of the switch fail.

[BODs SR2]

 

Bypassed everything with a direct battery feed and using that to activate the solenoid. Still same problem so I guess it’s internal. It seems however to be less frequent. 

[Tracy D'arth]

45 minutes ago, BODs SR2 said:

 

Bypassed everything with a direct battery feed and using that to activate the solenoid. Still same problem so I guess it’s internal. It seems however to be less frequent. 

That is interesting. Did you use a thick cable?

 

I would put a short wire, like 4mm CSA, on the small solenoid terminal and flash that onto the big terminal that goes to the battery via the isolator switch. If the solenoid then operates reliably, I would say the solenoid is OK and that the wiring or connections to the solenoid are insufficient. I am still not convinced that your batteries are as good as you think they are for starting a diesel engine.

You could just connect with a spanner but the sparks may frighten you.

[BODs SR2]

I used a large screwdriver to short across. May try another (newer) battery. 

[BODs SR2]

On 18/04/2022 at 11:06, Arthur Marshall said:

When this happened to me, it turned out to be a bad earth connection from the starter. Moved it somewhere else,  cleaned it up, and no more problems. Couldn't believe it was such a simple cure.

Checked that Arthur it’s fine. 

[Arthur Marshall]

8 minutes ago, BODs SR2 said:

Checked that Arthur it’s fine. 

Many people on here more qualified to advise than me. Good luck getting it sorted. As a side issue, if you're in RCR, they replace starters for free.

[BODs SR2]

On 18/04/2022 at 15:55, BODs SR2 said:

Can’t find it have you a link. May as well upgrade to this anyway. Cheers. 

Got the part off aes but no instructions. Contacted them but wondering if you could confirm how to wire in. Cheers. 

[Tony Brooks]

22 minutes ago, BODs SR2 said:

Got the part off aes but no instructions. Contacted them but wondering if you could confirm how to wire in. Cheers. 

 

Right, assuming it is not a solenoid equipped for a start inhibitor switch or a ballast resistance ignition system. Those two types have an extra terminal that may or may not need wirirng.

 

The two large nut terminals. A fairly heavy gauge wire from battery positive, ideally via  a fuse, to one connection say something around 4sq mm CCSA or larger. Another similar cable from the other terminal to the single small terminal on the starter solenoid. The wire you pulled off that small solenoid terminal to the small terminal on the new solenoid. Unless it is mounted on clean steel take a wire from one mounting bolt to battery negative.

[BODs SR2]

Fitted new solenoid ok. Still same problem. Noticed however that starter battery voltmeter reading falls off the scale when starting. Changed everything over to the fairly new service battery bank. Voltmeter reading drops slightly on starting. Still same problem however it seems more intermittent. 
 

Conclusion that starter needs attention however problem may be exacerbated by a weak battery. Have been advised elsewhere that for large twin engines the battery needs to be tip top. Will keep new solenoid in place as it does help the starter button. 
 

Thanks to all 👍