Should you allow fuel pump to Prime before starting boat?????

[oldmanskier]

I have a 2014 Carbon Pro with 5.7 PMC. Our club boat is a 2012 Mastercraft with 5.7 Ilmor.

On both boats some people in club will turn on key, wait till fuel pump quits bussing (priming) and then start boat.

Others just turn key and crank boat without waiting for fuel pump to finish priming.

For my boat (CP) I have them wait till fuel pump quits priming before cranking boat.

 

What is the correct procedure for starting boat:

Wait for fuel pump to prime and then crank boat?

Or

Just crank the boat with no wait?

Thanks

oldmanskier

 

[BraceMaker]

I wait a moment personally and listen.

[ForrestGump]

On current fuel injected engines there is no hurt in getting in and cranking it. Fuel systems have one way check valves in them to keep pressure from dropping after the pump shuts off. If you put a fuel pressure gauge on them with the boat off you'll see full fuel pressure. Essentially, there's no priming current fuel systems.

[Jody_Seal]

It can't hurt.. most dont.

[oldjeep]

Unless you have a leaky injector or a bad check valve there shouldn't be any reason a fuel injected motor needs to prime. No way to do what you are talking about anyways in a lot of modern boats - no keys, just pushbutton start.

 

[Andre]

Nobody let their car fuel pump prime before starting...

[eleeski]

Bubba, UCLA's old team boat requires a prime if it's been a while between starts. Gets you in the habit. At worst, if you forgot in Bubba, you had to turn the key off and try the restart procedure again with the prime.

 

My really old fuel injected Cessna requires a prime to start. If it's hot, the priming is a bit of an art to avoid flooding or starving.

 

Modern tech is great. You don't need to do any of that with your new boats. On second thought, the engine the club boat people have been abusing with the start procedure is shot. Send it to me for the American Skier re-engine project.

 

Eric

[oldmanskier]

If Jody says it cannot hurt that is good enough for me.

Thanks for all the comments.

oldmanskier

[gcam4]

I've always been an advocate of not letting the pump or injectors fire. My opinion is that it gives the oil pump that small amount of time more to prime before ignition.

[UWSkier]

I ski mostly in older boats with digital analog gauges. I usually turn the key and let them finish freaking out, let the ZO power up, then crank.

[LeonL]

What @Andre said makes sense to me.

[Fast351]

When you run your boat out of gas (yeah yeah) it helps to cycle on/off a few times to get fuel back into the rails.

 

[Waternut]

If I don't drive something regularly, I always turn it on for a second or two before cranking. In my mind, it's more of a systems check of the electronics before cranking. I think worst case scenario is you have to crank an extra second or two even if your fuel rail does lose it's prime.

[h2onhk]

glad i found this thread. I have an 07 196 with PCM 330. If I just turn the key over without letting fuel pump prime the engine will crank but makes a slight grind noise (almost sounds like starter disengaging then re-engaging) before firing or sometimes takes a second time before firing up. If I let the fuel pump prime completely it pops right over. Is this a starter issue or do I have a check valve going bad? Low pressure fuel pump?

[oldjeep]

@h2o.nhk - put a fuel pressure gauge on the rail and you will have your answer.

 

Cheap one like this works well enough, make sure you buy one with the bleed off valve as it can be useful for purging old fuel or air too.

 

amazon link

[Fast351]

I find that especially on older systems that may have a slow bleed down, or even newer cars that sit for a while, it helps to let the fuel system prime. Much easier to start.

 

If you have a fuel pressure rail bleeddown though, it's almost always the fuel pressure regulator on the return side of the rail. It's a manifold pressure referenced rubber diaphragm with a spring in it, and a vacuum hose that plumbs to the intake manifold. If the valve leaks, it'll bleed down. If the rubber diaphragm leaks though, it'll send fuel into the intake manifold, which can cause rich running, to stumbling, to in really bad cases flood and hydrolock the engine.

 

 

[BrennanKMN]

Driving diesel vehicles has gotten me in the habit of putting the key into run for a second or two before I flip it over to start. I often find myself doing the same with the boat. I put the key to run, once I hear PerfectPass beep I hit start.

I don't do it for the fuel prime though, just habit. I have never once had an issue starting my GT-40. I have even run it out of gas several times and had ski partners started it without a prime like it was full.

 

I do ski with a guy who has an older carbureted MasterCraft that I will prime and choke if it is cold. Otherwise just turn the key.

 

People often find a way to over think things. I know I do it. All I will say is do whatever makes you feel most comfortable.