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AQ170 ignition leads

i use 3000 - 7000 ohms/ft for suppressor leads...don't forget the shake them when measuring as they will break given enough time.
 
Thankyou, Volvo Penta manual I have says don't use resistive leads? Seem this engine has 3k to 7k ohm leads (NGK R-8) which looks to give weak spark when i test with the inline spark plug tester. Points and GT40 coil seem to test ok.
 
jimn said:
How old are they? What plugs are in it now? When I searched, I found NGK BP7HS. They don't need to be Volvo-Penta branded parts.
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Hi jimn, unsure of age they are NGK R-8 they don't look very old. Plugs are NGK bp7hs. They are resistive leads 3k to 7k ohm which seems incorrect according to Penta manual stating use non resistive leads?
 
no and yes, to your questions.

"seems" doesn't convey confidence with any conviction...

have you gone thru the rest of the secondary side yet??

Following the OEM manual is a good thing...you get need to appreciate that things change the further you get from their publication date...
 
makomark said:
no and yes, to your questions.

"seems" doesn't convey confidence with any conviction...

have you gone thru the rest of the secondary side yet??

Following the OEM manual is a good thing...you get need to appreciate that things change the further you get from their publication date...
Click to expand...
Have test all 7 ignition leads with multimeter - all test ok 5k to 3kohm
Checked distributor - ok
Re gapped points to spec.
Reset timing to spec at 2000rpm - ok
Test GT40 coil and input voltage - ok
Spark plugs gapped 0.7mm
Check all 6 leads with spark tester while motor running and removed plugs holding onto engine block negative - visually looks like weak spark (only small orange flash not bright audible crack).
 
Rotor condition??

Distributor cap age and condition?

GT 40 coils aren't the best replacements...some are happy with them and others arent...
 
Ventura said:
Have test all 7 ignition leads with multimeter - all test ok 5k to 3kohm
Checked distributor - ok
Re gapped points to spec.
Reset timing to spec at 2000rpm - ok
Test GT40 coil and input voltage - ok
Spark plugs gapped 0.7mm
Check all 6 leads with spark tester while motor running and removed plugs holding onto engine block negative - visually looks like weak spark (only small orange flash not bright audible crack).
Click to expand...
Find a different wire from the coil to the distributor cap- any coil or spark plug wire. If you can't find one, use any kind of wire, just for testing. For some reason, I used to see more bad coil wires on Ford engines, but a new coil wire for diagnostics showed where the problem existed. I actually used speaker wire and the engine started. If all spark plugs have weak spark, testing each is pointless- you need to check something that's common to all of them.

While you're at it, clip one end of a wire onto the distributor base and the other on something that you know is well-grounded. If it works, shut it off and clean the area where the distributor is mounted, so it makes better contact.
 
jimn said:
Find a different wire from the coil to the distributor cap- any coil or spark plug wire. If you can't find one, use any kind of wire, just for testing. For some reason, I used to see more bad coil wires on Ford engines, but a new coil wire for diagnostics showed where the problem existed. I actually used speaker wire and the engine started. If all spark plugs have weak spark, testing each is pointless- you need to check something that's common to all of them.

While you're at it, clip one end of a wire onto the distributor base and the other on something that you know is well-grounded. If it works, shut it off and clean the area where the distributor is mounted, so it makes better contact.
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Ok thanks jimn, I checked everything you suggested and no reaI difference. Also took the boat for a spin yesterday and would not get over 3000rpm under load without backfiring. Also felt like it was running quite rough. When I got back I checked ignition system again and fuel system all checked ok. Still has spark all cylinders however looks weak to me (Maybe im wrong and it's ok for these old Volvo's) Also did another compression check and all cylinders around 115 psi (+- 5psi).
Would this be considered low enough compression to cause issues im having? I couldn't see any signs of water in cylinders.
Im nearly ready to pull this engine and convert the boat to pod/outboard. If its a compression issue I certainly will.
 
Ventura said:
Ok thanks jimn, I checked everything you suggested and no reaI difference. Also took the boat for a spin yesterday and would not get over 3000rpm under load without backfiring. Also felt like it was running quite rough. When I got back I checked ignition system again and fuel system all checked ok. Still has spark all cylinders however looks weak to me (Maybe im wrong and it's ok for these old Volvo's) Also did another compression check and all cylinders around 115 psi (+- 5psi).
Would this be considered low enough compression to cause issues im having? I couldn't see any signs of water in cylinders.
Im nearly ready to pull this engine and convert the boat to pod/outboard. If its a compression issue I certainly will.
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Did yopu check timing advance at idle?

Compression at 115 is low.

What kind of spark tester are you using?
 
jimn said:
Did yopu check timing advance at idle?

Compression at 115 is low.

What kind of spark tester are you using?
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Yes rechecked the timing was advancing from idle with timing light. Timing would increase upto 26deg at 2000rpm and kept increasing to 2500rpm. I didn't check high rpm being no load. I also check the distributor Weights were not sticking by moving them with a screwdriver, weights and springs seem ok.
Spark tester is a Tool pro inline light type tester.
 
Ventura said:
Yes rechecked the timing was advancing from idle with timing light. Timing would increase upto 26deg at 2000rpm and kept increasing to 2500rpm. I didn't check high rpm being no load. I also check the distributor Weights were not sticking by moving them with a screwdriver, weights and springs seem ok.
Spark tester is a Tool pro inline light type tester.
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I meant, did you check the idle advance AT idle without raising the RPM? Base timing isn't usually at 0°BTDC.
 
on the spark, did you check the primary voltage at the coil? could be the harness has degraded and there are one or more unintended voltage drops occurring between the battery and the coil.
 
makomark said:
on the spark, did you check the primary voltage at the coil? could be the harness has degraded and there are one or more unintended voltage drops occurring between the battery and the coil.
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I was getting about 6 volts across coil primary winding when engine is running.
 
jimn said:
I meant, did you check the idle advance AT idle without raising the RPM? Base timing isn't usually at 0°BTDC.
Click to expand...
I did not check idle 900rpm timing as the damper markings are only from 26°. I will try clean up the damper more to find a 12° marking. However I just notice my distributor is a 008 model and the manual I have is saying to set it at 32-34° @2000rpm? I will give this setting a try and see if there's any improvement.
 
Ventura said:
I did not check idle 900rpm timing as the damper markings are only from 26°. I will try clean up the damper more to find a 12° marking. However I just notice my distributor is a 008 model and the manual I have is saying to set it at 32-34° @2000rpm? I will give this setting a try and see if there's any improvement.
Click to expand...

You still need to know base timing.

Also, what scale are you using when you see 6V- AC or DC? Do you see 12VDC when the key is on/engine off?

Hold your horses! You gapped the plugs at .7mm? That's only .027" and that's in the same range as the points gap spec.
 
Ventura said:
I was getting about 6 volts across coil primary winding when engine is running.
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6 VDC is low for a 12v system....

I'd be inclined to check the aftermarket coil to see if it needs a resistor - very possible there is an 'extra' one.

On the point gap, best to check it with a dwell meter...you should find the spec range on the same page you found the gap.
 
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