Motor starts and only runs for a few seconds & shuts down. I don't think it's fuel because if I pump the throttle while it is stopping it has no effect on it. I've not tested any ignition components yet. Any ideas on where to start will be appreciated
Thanks, M

Does it run only when key is in the start position or does it run a couple seconds after the key is released to run? Could be as simple as deadman switch. Put. A test light or run a wire to purple (+) terminal of the coil and bypass whole boat and see if it stays running.

put a timing light on it. light quits blinking, you know spark has left the building...

Not to sound demanding but you need to post year and the model number of the engine very important to receive correct info about your specific app.

My guess is electric fuel pump
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Simple laymens test after engine shuts down and no restart - unscrew the water fuel sep filter and if that filter is not completely over flowing fuel out of it, then the fuel pump is not pumping enough fuel to feed the carb / engine. Also it is wise to change this filter twice per year.

Next laymens test is --- You can unscrew the fuel line at the carb and shove a milk jug over the fuel line - crank engine over for about 3 to 5 seconds --- you should have a lot of gas going into the jug.



The best way is use a fuel pressure gauge testing method. I posted the other 2 ways cause my guess would be ---- not having a fuel pressure gauge and the correct fitting to do the testing.

Also check for power at the fuel pump its self. Make sure that end of it is good

My guess is the electric fuel pump is bad.

I'm with you Bup, I would say fuel also,but since OP says it will start, but it stops running after a few seconds, it sounds to me more like a relay or an oil pressure switch isn't working to keep pump running while engine is running.

I do not know the Volvo set up, but I do know on most electric pump equipped engines the electric pump will lose power when something doesn't 'see' the engine is still running.

Other words, there is a power system to pump for starting purposes. Once engine starts and runs, this system turns off as another power system takes over when engine is running. Many use an oil psi switch,some use a feed of the alternator , and some use other means. This is for safety reasons as no one wants a fuelpump running if an engine is not running. Say there is a fuel line that came off or worse yet,the vehicle tips upside down. which points out reason why most cars need to see oil psi for fuel pump to continue to run.

But, here we go with another thread that has an issue, is looking for a common issue,but has not performed any diagnostic work yet.

If it's a carb GL it gets 12v to the pump relay thru the starter solenoid when cranking and then thru alt when it's running, volvo doesn't use a oil pressure switch pump interlock.

BUP, you are correct I should have given more info. Sorry. It's a 2000 4.3gl carb engine. I bought not running due to a fuel pump wiring issue(and fuel pump is missing) . However I temporarily installed a 12v fuel pump and wired it straight to the battery for test purposes only. So I'm pretty sure we have plenty of fuel. I'm not familiar with volvos ignition system but I'm suspicious that I have there. I'll be digging in a little deeper this week and will try some of the suggestions posted here. Thanks for the info guys! M