Volvo Penta 5.7 (570a) carb no spark

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QBhoy

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Hi guys. I’ll try and summarise to keep it brief.
Last night whilst out a sail on my own wee boat, I had a call from a friend who’s boat wouldn’t fire at the mooring. We went to half a semi serious look (didn’t have Work wear on so not too involved). It was turning over but not even trying to fire. Normally a really great starter.
Getting fuel, Diz cap good. Coil getting power either side and retains its insulation. Just no spark. Took coil from another known good boat and the same.
After sleeping on the problem and looking at a few wiring diagrams, would I be far off in thinkin this will likely be an ignition feed problem ? As I’m either the ignition barrel or ignition sensor at or in Diz? Or a broken or loose wire in between ? Anyone have a similar experience? Also sticking in my mind that the key was able to be removed with ignition on. Surely shouldn’t happen ?
 
HT lead between coil and Diz cap .
Sometimes you can unplug the Diz cap end ,hold it very close to the engine block while somebody turns over the engine with the key momentarily to see if there’s a spark .

Perhaps carry a spare set of HT leads ?

If there is a good spark ,then I,d be looking at the fuel pump .
It will have an electric fuel pump .
If it’s been stood for while this needs say 20 sec,s or so with the ignition on the 1st click to prime the carbs fill the float chambers enough before the 2nd position to crank .
You can normally hear the fuel pump whirling on the 1st click .
 
Last edited:
Hi Portofino
I tried that last night. No spark coming from coil to Diz on king lead.
Defo not fuel related either.
I think it might be that the ignition isn’t giving a feed to fire. It’s almost as if it’s interlocked. Doesn’t have a lanyard thoigh and not the “I think I’m in gear” interlock either.
 
You say the coil has oower either side so the ignition feed is OK. The coil gets a 12v supply when the ignition is on and it goes through the coil and earths through the ignition module which switches the earth on and off so the coil gives a spark at the right time. Connect a test light to the negative terminal of the coil and crank the engine, it should flash on and off if the module is working, if it stays on or off then the module is faulty. If it flashes then the coil primary circiut is working and your fault is on secondary (high tension) side so I’d be checking if there is a spark from the ht lad on the coil and everything downstream i.e. rotor, cap etc.
 
QBhoy said:
Hi guys. I’ll try and summarise to keep it brief.
Last night whilst out a sail on my own wee boat, I had a call from a friend who’s boat wouldn’t fire at the mooring. We went to half a semi serious look (didn’t have Work wear on so not too involved). It was turning over but not even trying to fire. Normally a really great starter.
Getting fuel, Diz cap good. Coil getting power either side and retains its insulation. Just no spark. Took coil from another known good boat and the same.
After sleeping on the problem and looking at a few wiring diagrams, would I be far off in thinkin this will likely be an ignition feed problem ? As I’m either the ignition barrel or ignition sensor at or in Diz? Or a broken or loose wire in between ? Anyone have a similar experience? Also sticking in my mind that the key was able to be removed with ignition on. Surely shouldn’t happen ?
Click to expand...

Do you have a kill switch ? If so could be faulty
 
Hi guys
Feel rotten for only logging on now and realising that you had all offered such help...so appreciated!
As perhaps suspected...it was the ignition sensor/module/amplifier or what ever some may call it. It’s a spherical device in the Diz on these models. Wasn’t sensing the ignition and hence giving the notion to fire.
Thanks again all.
 
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