Changed plugs now no start

Maverick16

Cadet
Joined
Jun 22, 2022
Messages
14
Hey guys I've been reading this forum for awhile now, lots of great info, it has helped me solve a quite few issues. So thanks for that
However I have a new issue that seems to not have been asked before... or I cant find it. here goes.
Boat was running fine out of water, put it into lake no start, pulled it out and it started right away...i believe it is a back pressure issue. Battery was a bit low 9.5, charged it, ran some throttle body cleaner through the carb and figured I'd check the compression. I also figured while I was checking compression I would put new plugs in. So off I went. I pulled all the plug wires and 1 by 1 checked compression(engine cold) all compressions were 148 - 150. replaced all the plug wires, correctly.

When I try to start the engine it turns over and seems like it will fire but when I release the key it stops. If i keep the key in the start position she will continue to run.

Any help is appreciated.
Volvo 4.3gl
 

dubs283

Vice Admiral
Joined
Jul 27, 2005
Messages
5,337
Battery was a bit low 9.5, charged it.......When I try to start the engine it turns over and seems like it will fire but when I release the key it stops. If i keep the key in the start position she will continue to run.
9.5 volts is more than a bit low, it's a lot low. Charge the battery overnight then load test it the next day

Running while cranking then dying is an indication of possibly operator presence/lanyard switch off. Most carbureted Volvos of your vintage have an ignition bypass wire to aid the primary side of the ignition coil with firing that is energized during cranking. Once the engine fires and the operator returns the key to the run position the circuit is no longer energized and the primary ignition circuit wire provides voltage to the coil primary. Operator presence switch is in line with the ignition wire between the key switch/dash and the engine
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,459
yes that was the issue thank you.
Just an FYI. At 9 volts, the ignition will not work and there is no way to spin the motor fast enough.

Most batteries are 100% depleted at 12.0 - 12.2 volts, and fully charged at 12.7-13 volts (depending on battery architecture).

Below 12 volts, you run the risk of toasting the battery
 
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