Starter motor issues

[Roy Masters]

I'm refitting my narrowboat and having issues with the starter motor. According to the literature that came with the boat the engine is a Perkins 4.108 engine but this is where my problems start. According to Perkins this engine has a starter motor with 10 teeth but mine has 13 teeth so the new one purchased that had the recommended 10 teeth would obviously not mesh. If anyone has any suggestions as to where I can locate a stater motor with 13 teeth I would be extremely grateful. I have located the engine number but this does not register with Perkins. The engine is from the 80's.

[Ex Brummie]

First of all, is your engine a 4.108 that has been independently marinised, or is it a 4.108M with a large flywheel .

My 4.108M has a starter motor which has a set of planetary gears on the output shaft, and is fitted to the engine with a spacer. In the erly 2000's it was only available from Lucas as a service exchange.

It is possible to fit the standard automotive type which fits without the spacer but you need the correct no of teeth to engage it.

What is wrong with your motor? Can you not get it repaired/overhauled?

[Momac]

22 minutes ago, Roy Masters said:

I'm refitting my narrowboat and having issues with the starter motor. According to the literature that came with the boat the engine is a Perkins 4.108 engine but this is where my problems start. According to Perkins this engine has a starter motor with 10 teeth but mine has 13 teeth so the new one purchased that had the recommended 10 teeth would obviously not mesh. If anyone has any suggestions as to where I can locate a stater motor with 13 teeth I would be extremely grateful. I have located the engine number but this does not register with Perkins. The engine is from the 80's.

Are you sure the engine is a Perkins?

[Roy Masters]

It has a Perkins plate on the top and the literature from the seller states Perkins.

 

[Roy Masters]

The engine number is ED5021BU628338Pwhich Iam lead to believe is a Perkins number and the starter motor  has LUCAS 54253208 stamped in the body if this is any help to anyone.

[Roy Masters]

1 hour ago, Ex Brummie said:

First of all, is your engine a 4.108 that has been independently marinised, or is it a 4.108M with a large flywheel .

My 4.108M has a starter motor which has a set of planetary gears on the output shaft, and is fitted to the engine with a spacer. In the erly 2000's it was only available from Lucas as a service exchange.

It is possible to fit the standard automotive type which fits without the spacer but you need the correct no of teeth to engage it.

What is wrong with your motor? Can you not get it repaired/overhauled?

I cannot answer any of your questions at the moment because I just don't know. I will be looking to get the existing motor overhauled but it is finding the right company.

[MtB]

8 hours ago, Roy Masters said:

I cannot answer any of your questions at the moment because I just don't know. I will be looking to get the existing motor overhauled but it is finding the right company.

 

Hold on. Don't run ahead of yourself. 

 

In your OP all you said was that you are "having issues" with it.

 

What issues? Many starter "issues" are caused by wiring, battery or earth strap faults, not the starter motor itself. You could be wasting a tonne of money assuming the motor is faulty without diagnosing it properly first. Describe the issues and you'll get plenty of advice here about how to pin it down.

 

 

[Tony Brooks]

It might be a 4-107, visually very similar to the 4-108

[BEngo]

Wot MtB said upthread. First

  Then

If your  starter motor needs expert  attention the folk to talk to are Lancashire Rotating Electrical.  I have used them a fair bit, as have others on here, and they are good.  They can arrange transport for your motor both ways.

 

Usual disclaimer.

N

[MtB]

The really easy error to make is not checking the earth strap.

 

The BMC 1.8 I've just been working on had an apparent starter motor failure. Another engineer attended initially and he jumped to the conclusion the motor had failed and fitted a brand new one. New one didn't work either and he walked away, completely stumped. So I picked up the problem and found the earth strap was not making a good connection. Once fixed, the new starter ran fine and I suspect the old one (still in the engine bay) is probably fine too. 

 

 

[Roy Masters]

21 hours ago, Ex Brummie said:

First of all, is your engine a 4.108 that has been independently marinised, or is it a 4.108M with a large flywheel .

My 4.108M has a starter motor which has a set of planetary gears on the output shaft, and is fitted to the engine with a spacer. In the erly 2000's it was only available from Lucas as a service exchange.

It is possible to fit the standard automotive type which fits without the spacer but you need the correct no of teeth to engage it.

What is wrong with your motor? Can you not get it repaired/overhauled?

 

[Roy Masters]

According to the paperwork that came with the boat the engine is stated as 4.108. I don't think there are any planetary gears fitted.

 

[Ex Brummie]

I assume you have already removed the motor as you have counted the cogs. If so, I would refer back to the supplier of the incorrect replacement and ascertain whether they can offer an alternative. 

[MtB]

4 minutes ago, Roy Masters said:

According to the paperwork that came with the boat the engine is stated as 4.108. I don't think there are any planetary gears fitted.

 

 

Frankly, "the paperwork" is probably someone's best guess just from looking at it. What paperwork do you have, exactly, that says its a 4108?

 

I think there is bound to be a way to differentiate a 4108 from a 4107, but these are not common engines in a narrowboat so there may not be a great deal of expertise here.

 

 

[Roy Masters]

58 minutes ago, MtB said:

 

Frankly, "the paperwork" is probably someone's best guess just from looking at it. What paperwork do you have, exactly, that says its a 4108?

 

I think there is bound to be a way to differentiate a 4108 from a 4107, but these are not common engines in a narrowboat so there may not be a great deal of expertise here.

 

 

 

"The paperwork" is what was given to me by the agent at the marina I purchased the boat. I can  only use what I have.

[jonathanA]

4 minutes ago, Roy Masters said:

 

"The paperwork" is what was given to me by the agent at the marina I purchased the boat. I can  only use what I have.

Indeed but you do need to exercise some judgement as to how much you rely on that paperwork. If you have a perkins manual where the serial number of your engine is quoted then that's pretty concrete. On the other hand if all you have is some sales blurb from the broker then it's probably highly unreliable....

[Roy Masters]

1 hour ago, MtB said:

The really easy error to make is not checking the earth strap.

 

The BMC 1.8 I've just been working on had an apparent starter motor failure. Another engineer attended initially and he jumped to the conclusion the motor had failed and fitted a brand new one. New one didn't work either and he walked away, completely stumped. So I picked up the problem and found the earth strap was not making a good connection. Once fixed, the new starter ran fine and I suspect the old one (still in the engine bay) is probably fine too. 

 

 

Many thanks, I will check this out tomorrow when I am next at the marina but since I am a complete novice at this is the earth strap really obvious to spot or can they be in different positions?

[jonathanA]

Sorry if I missed it what is the problem with the old starter ? Just clicking ? Nothing or very slow ? 

 

I went to a boat Tuesday "not starting" was just clicking the owner was about to buy a new battery until I simply tightened up the battery connections and the engine started....

[Tony Brooks]

4 hours ago, Roy Masters said:

Many thanks, I will check this out tomorrow when I am next at the marina but since I am a complete novice at this is the earth strap really obvious to spot or can they be in different positions?

 

If you are thinking car type earth straps, then no, not immediately obvious. It is likely to be a length of insulated cable about 1/2" OD. One end fixed to the start battery negative and the other end bolted to the engine bed or engine block/starter negative terminal. Whichever it is, ideally it will then connect that to the alternative. So battery > engine > bed or Battery > bed > engine. (Note that is the way to follow it, with "normal" current flow it will be going the other way).

[Roy Masters]

On 05/11/2025 at 17:52, Tony Brooks said:

 

If you are thinking car type earth straps, then no, not immediately obvious. It is likely to be a length of insulated cable about 1/2" OD. One end fixed to the start battery negative and the other end bolted to the engine bed or engine block/starter negative terminal. Whichever it is, ideally it will then connect that to the alternative. So battery > engine > bed or Battery > bed > engine. (Note that is the way to follow it, with "normal" current flow it will be going the other way).

Thanks Tony. Do you know of any good starter motor reconditioners local to West Midlands?

[Tony Brooks]

8 hours ago, Roy Masters said:

Thanks Tony. Do you know of any good starter motor reconditioners local to West Midlands?

 

No, I live and worked in the South, but a Google for alternator and starter repairs usually throws up a few options.

 

I will repeat the question that seems not to have been answered. Exactly what is this "problem". Unless we know, as you may have fund, you will get all sorts of advice that may send you off on the wrong track. Please describe what this problem is, unless you just want another/overhauled starter.

 

4-108s are so old, I would not put too much trust in the Lucas number, because it is perfectly possible the body has been changed without erasing the part number.

 

It might help to see a photo of the starter and the engine, although telling the difference between the 4-106, 4-107 and possibly the 4-99 could be difficult. Some Perkins of that age used an inertia starter rather than the normal pre-engage.

[cuthound]

11 hours ago, Roy Masters said:

Thanks Tony. Do you know of any good starter motor reconditioners local to West Midlands?

 

Cox Auto Electrics, Atherstone 

 

https://www.coxautoelectrics.co.uk/

[MtB]

There is also Electro Start Ltd in Daventry. 

 

Not used them myself but I've heard people speak highly of them.

 

https://electrostart.co.uk/

 

 

 

But before shelling out £400 on another starter you may not need, best to describe the fault on here for confirmation it isn't something simple you're overlooking. 

 

 

[ditchcrawler]

7 hours ago, MtB said:

There is also Electro Start Ltd in Daventry. 

 

Not used them myself but I've heard people speak highly of them.

 

https://electrostart.co.uk/

 

 

 

But before shelling out £400 on another starter you may not need, best to describe the fault on here for confirmation it isn't something simple you're overlooking. 

 

 

Had them do an alternator, 24V ex truck

[MtB]

33 minutes ago, ditchcrawler said:

Had them do an alternator, 24V ex truck

 

And?!