Engine Start Relays

dragoon

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Hi,
I wonder if anyone can help throw some light onto the following.

A year or so after buying our boat, one of the starter relays packed-up. It would click, but was not able to pass any current and so the starter motor would not even try to engage. It could easily be bypassed by shorting a thick screwdriver across the terminals, so this was definately the source of the problem, and I changed the relay (70 pounds!! Ahem!!).

Last year, the other engine exhibilited the same problem, and again I replaced the starter relay. Another 70 pounds to Volvo.....

Now this year, the original one I replaced has failed in the same manner. I appreciate it's 3 or 4 years later, but I don't use the boat that often as I believe it can be worn out.

Can anyone throw any light on this? The engines are TAMD40Bs. Is this normal? Could this be a symptom of starter motors or solenoids that are failing and leading to a premature degrading of the relay contacts?

Any help much appreciated before I order another 70 pounds plastic box with 4 terminals.....

Cheers,
Paul
 

orizaba

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its quite possible that the starter motors are drawing more current through the relay,over the years they can degrade a bit and brushs wear etc and they need more ooompth to get them going, the only way to tell would by connecting an ammeter bettween battery and starter motor and measuring the amps used,not an easy task as it takes alot of amps and not easy to find a meter that would measure it,probabally not very cost effective either
i would have expected the relay to last longer than 3 years, in the commercial lorry world they would last 10 years plus and often be in very exposed places.
taking it that your engine still starts the same way as it always has,ie you don't have to crank it over much more now than you did a couple of years ago,then not much should have changed,the starter motor as it ages can get a bit more sluggish and need more amps to start it but you would normally notice that.
if your starter moters are easy to access /remove it might be worth getting them tested by an auto electrician repair
place,we had a local lucas's who repaired diesel pumps injectors alternaters,starter motors etc, they may also be able to sell you a smilar relay or better for less money, if not try a local trade type car and commercial spares outfit,most of these parts are similar/interchangeable,obviously take the old one with you and any other details on the engine you may have.
at least if you get them tested you would know for sure and quite often a cleanup of brushs and armature can work wonders,
 

MrCramp

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Don't know anything about TAMD40Bs but I would replace the relay with one from a car spares shop, or even from a scrap yard. I ran Volvo cars with 2.3ltr engines and never ever had a problem with the starter relays, even after 16 years and 220,000 miles. I would try and avoid buying anything from a marine Volvo agent.
 

volvopaul

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Hi next time it goes dont bother going to volvo take it to a good auto electrical retailer they will pattern it up, as it has one live feed from the starter, one earth, one output to starter motor and a feed from the ignition switch, so its not complicated, I think though it has to be about a 50/60 amp relay so its a bit special compared to one that does lights or electric windows etc, I take it the relay that does the glow plugs is ok.

The old paris rhone starters are better that its new valeo replacement, if the starter packs up then I would get it repaired rather than buy a new valeo one.
 
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