Long crank time on carbuerated engine

[ymmot60]

Hello everyone,

Looking for the wisdom of others with regards to my 1996 mercruiser 4.3L V-6 motor, electric fuel pump, carbuerated. While out on the lake it takes 5-8 seconds of cranking time for the motor to catch. This seems like a long time (especially while the safety alarm is screaming at you). Is this normal for curbuerated systems when they've been working (wakeboarding/tubing/cruising) . When launching the boat the engine fires after only a couple seconds.

If I disengage the prop and start while giving gas, it will start quicker. This leads me to wonder if the engine is being starved although it runs fine under load.

Thanks for any input.

 

[mpdive]

Re: Long crank time on carbuerated engine

Sounds to me as if you have a mal-adjusted choke problem. A cold engine requires a rich mixture. If you have a "tight" choke it would enable you to have easy cold engine starts but difficult and rich hot starts. Pull the dog house on the hot engine and observe the choke plate. If all is fine, I would suspect the bowl is leaking down upon sitting. The extended crank would account for refilling the fuel bowl. When you observe the choke, pump the throttle one time while looking down the barrel of the carb. You should see a strong stream of fuel down the venturi.

 

[HT32BSX115]

Re: Long crank time on carbuerated engine

Hello everyone,

Looking for the wisdom of others with regards to my 1996 mercruiser 4.3L V-6 motor, electric fuel pump, carbuerated. While out on the lake it takes 5-8 seconds of cranking time for the motor to catch. This seems like a long time (especially while the safety alarm is screaming at you). Is this normal for curbuerated systems when they've been working (wakeboarding/tubing/cruising) . When launching the boat the engine fires after only a couple seconds.

If I disengage the prop and start while giving gas, it will start quicker. This leads me to wonder if the engine is being starved although it runs fine under load.

Thanks for any input.

Howdy,


It's fairly normal for a bit of a crank when starting a carbureted engine.

We've probably all been "spoiled" a little by the instant starting of EFI engines and ANY cranking seems long!

It's also possible that your idle mixture is somewhat "lean" causing you to crank a bit......your float level might be a tad "low" too.

Also, you would want to check the auto-choke operation to see if it's not opening all the way when the engine is hot.
(I disconnected mine altogether on my 7.4L V-8....I only boat in warm weather and just don't need it)

You might also try giving the engine a couple of "pumps" right before cranking. I have to do that with mine.

Look in the carb with the engine OFF. Have your helper pump the throttle idle-full once or twice and see if it pumps fuel. If not, your accelerator pump is defective and your carb probably needs a rebuild.


Regards,


Rick