93maxum4.3lx
Seaman Apprentice
- Joined
- Aug 2, 2008
- Messages
- 34
mercruiser 4.3lx, 1993, 4bbl, electric fuel pump.
If the boat hasn't been used for a week or two, it takes a while to start. Here's how it typically goes:
* crank for about 5 seconds - oil pressure gauge is flickering with pressure by 5 seconds
* wait 10 seconds
* pump gas once
* crank for another 5 seconds - solid 5-10psi pressure
* wait 10 seconds
* pump gas once
* crank for another 5 seconds
typically, about 4-5 seconds into the third cranking, she fires up; so I'm looking at about 15 seconds of total cranking..which is of course hard on the starter and batteries and such.
I researched the fuel system here on the forums, and the carb'd setup does NOT prime the pump when you first turn the key to run.. the fuel pump only runs in START, and when there is oil pressure.
So, I tried priming the fuel pump a few hours before launching the boat; i ran the pump by directly powering it for 20 seconds or so.
This time, she started up after only 3-4 seconds of cranking..much nicer!
Questions:
How long does a typical 4.3 carb/electric pump take to fire up after sitting for a week or more?
Should the system be holding it's prime better? (Is there a one way valve anywhere in the sytem)?
I've thought about wiring a pushbutton to the oil pressure switch and mounting it near my battery switch - something I could press for about 20 seconds when I first turn the battery on for the day, to prime the system and make starting easier.
thoughts?
If the boat hasn't been used for a week or two, it takes a while to start. Here's how it typically goes:
* crank for about 5 seconds - oil pressure gauge is flickering with pressure by 5 seconds
* wait 10 seconds
* pump gas once
* crank for another 5 seconds - solid 5-10psi pressure
* wait 10 seconds
* pump gas once
* crank for another 5 seconds
typically, about 4-5 seconds into the third cranking, she fires up; so I'm looking at about 15 seconds of total cranking..which is of course hard on the starter and batteries and such.
I researched the fuel system here on the forums, and the carb'd setup does NOT prime the pump when you first turn the key to run.. the fuel pump only runs in START, and when there is oil pressure.
So, I tried priming the fuel pump a few hours before launching the boat; i ran the pump by directly powering it for 20 seconds or so.
This time, she started up after only 3-4 seconds of cranking..much nicer!
Questions:
How long does a typical 4.3 carb/electric pump take to fire up after sitting for a week or more?
Should the system be holding it's prime better? (Is there a one way valve anywhere in the sytem)?
I've thought about wiring a pushbutton to the oil pressure switch and mounting it near my battery switch - something I could press for about 20 seconds when I first turn the battery on for the day, to prime the system and make starting easier.
thoughts?
