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Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 10895
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
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Tan ... I have a mercruiser 4.3 ... Just launched off the

Customer Question

Hi tan ... I have a mercruiser 4.3 ... Just launched off the boat ramp and for the first time it just turns over but won't fire ...
Submitted: 1 year ago.
Category: Boat
Expert:  Tan replied 1 year ago.


Have you checked for voltage at the ignition coil purple wire key on?

We need to determine if we have voltage to the ignition coil and see if it is a voltage issue or an ignition system failure.

Could I get the engine serial number please?

Customer: replied 1 year ago.
Hi there I will send the engine number this morning (8am here)I am camping without a multimeter with closest town 1 hour away and most business' closed as it is Sunday
Expert:  Tan replied 1 year ago.

Ok do the gauges come on when you turn the key on?

We will need a meter to do some voltage testing.

I'm in Az on mountain time. It is 3:30 now.

Customer: replied 1 year ago.
Ok ... Serial number of engine is GM12552422Since my reply this morning I have attempted the following :- back to boat ramp to submerge leg
- tried to start - failed
- removed carbie cover to check that fuel was entering system when pumping throttle in neutral - confirmed
- kicked engine over with cover removed - sounded like it wanted to start
- replaced cover -
- kicked over engine and after some time it fired and started ! Woo hoo but it died after about 5 seconds ...
- pumped and started again - this time maybe 20 seconds before dyingOther boats want to launch so I'm back at campThe silver grill cover on inspection was covered in grime so I have wiped that clean - would that cause a lack of air problem ??Have attached some photos for you
Customer: replied 1 year ago.
Going to try again with the clean filter
Expert:  Tan replied 1 year ago.

If the cover of the carb(flame arrestor) is clogged it can cause flooding. But the engine will run ok if the cover is removed eliminating the cover(flame arrestor) as the problem.

With throttle in the fully wide open position look down in the carb do you see fuel puddled in the bottom of the intake manifold?

Try this put the throttle in the fully wide open position crank the engine. Keep hand on throttle handle. Does engine start?

It is possible the engine is flooded from a stuck inlet needle in the carb flooding the engine with to much fuel.

Post back with findings.

Customer: replied 1 year ago.
I saw fuel puddled in the bottom of the carbie- even with throttle in fully open position the engine does not startI can't get it to start again like it did this morning. I have checked oil and next will try to remove the fuel filter to see if it is clean or not
Expert:  Tan replied 1 year ago.

Puddled fuel is one of 2 things flooding carb or no spark. We need to check for spark to eliminate that as the cause for your issue. If we have spark then the carburetor is the problem. If you have to much fuel it will fool the spark plugs and the engine won't start.

There are a couple of ways to check for spark. You can pull the coil wire out of the top of the ignition coil and hold it about 1/2 from the top of the coil where you pulled it from the coil crank engine. The spark should arc blue spark.

If you have spark then you will need to remove the carburetor and have it rebuilt. If no spark post back. We will need the engine serial number which will be in one of the following location in this link below. The number you posted earlier isn't engine serial number. That is a part number for the intake manifold.

Customer: replied 1 year ago.
Hi Tan, we were hit with a storm at the camp site last Sunday during our conversation. Following that the phone service was limited and access to the internet failed. The tyranny of time delay to our conversation became quite hard for me to work with - in the end i took the boat to a local mechanic on Monday last week. The issue was the Ignition module being shot in the Distributor - i had them replace the fuel filter at the same time. Back on the water within two hours. The back and forth to fix this when i don't have too much engine knowledge made this transaction too hard for me. Thanks and regards ***** *****
Customer: replied 1 year ago.
I do not intend to rate the service as bad at all - it just didn't suit my requirements at the time. I do not however expect that the full cost will be charged - who do i discuss this with ? regards sv
Expert:  Tan replied 1 year ago.

Hi Shannon. Glad you got the issue resolved. You will have to contact customer service for help with this issue.

I am a subcontractor and have nothing to do with the billing process.

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