Hard starting after changing water separator

[TexasA&M]

I finally got around to changing my oil and water separator this weekend and remembered why I hate changing the fuel filter... it takes me FOREVER to get the boat started afterward! I actually never did get it running yesterday; I ran out of daylight and had to finish some other stuff up before it got dark.

What is the correct procedure for changing the filter and then getting the engine running again? I tried starting it for about an hour yesterday, and all it would do was sputter. I remember messing with it for at least as long the last time I changed the filter too. Any tips on making this an easier process?

 

[JimG]

Fill the new filter with fresh gas before installing.

 

[TexasA&M]

I thought about that, and may have to go that route if I can't get it started. The biggest problem with doing this is the mess that I will inevitably make!

 

[Lazy Daze]

In addition to filling (or at least partly filling) the filter... When you turn your key on, you'll hear (in addition to the warning buzzer) the fuel pump run. Once the pump stops, turn the key off and then back on again to activate the pump. Do that a half dozen times and you should be good to go. Sometimes it takes less KO-KO, sometimes more. Works with an empty filter, too.

 

[Gunn]

Fill the new filter with fresh gas before installing.

What Jim said. :smt001 No mess as long as you are careful. Fill it up off the boat and carefully carry it onboard and install. Use a rag around the filter to remove it carefully without denting or otherwise ruining it. It's easier on the engine, starter and batteries if you fill it. She'll fire right up and you'll be good to go.

 

[Dave 205]

In addition to filling (or at least partly filling) the filter... When you turn your key on, you'll hear (in addition to the warning buzzer) the fuel pump run. Once the pump stops, turn the key off and then back on again to activate the pump. Do that a half dozen times and you should be good to go. Sometimes it takes less KO-KO, sometimes more. Works with an empty filter, too.

Dennis, when I bought my boat (used) the dealer took me out for a demo, and had me pump the throttle a few times before turning the key on my carb 5.0. When it didn't fire (after sitting for a few month) he had me pump it several more times. It worked. I've done this pumping after changing the fuel filter, and it seems to work. Is this wishful thinking or legitimate? I've dumped a bit of fuel into the filter to speed this up, but left it half empty to keep installation clean.

 

[src]

If you have a mechanical fuel pump and a carb'd engine, then nothing but cranking the engine will fill the filter. Pumping the throttle just squirts some of the fuel from the lines into the carb. If you have enough fuel in the lines, then that might get you over the "hump" as the filter fills.

With an electric fuel pump and injectors, the pump has to build pressure to put fuel into the injectors, so it has to fill the filter first. That's why the key on/off cycle can work - when you turn the key on (but not to start), the pump runs a little to try to build system pressure before starting. Enough cycles and it will load up the filter.

Best to just pre-fill the filter when changing it, though.

 

[TexasA&M]

I have filled the filter and turned the key on an off for an hour now, still no luck. Do I just need to keep turning the key on and off? I'm running out of ideas!

 

[Lazy Daze]

Dennis, when I bought my boat (used) the dealer took me out for a demo, and had me pump the throttle a few times before turning the key on my carb 5.0. When it didn't fire (after sitting for a few month) he had me pump it several more times. It worked. I've done this pumping after changing the fuel filter, and it seems to work. Is this wishful thinking or legitimate? I've dumped a bit of fuel into the filter to speed this up, but left it half empty to keep installation clean.

Pumping the throttle is useful for cold starts (sometimes for hot starts) with a carb'd engine. But doing the pumping doesn't really do much as far as after a filter change. You still have an electric fuel pump and that is what is doing the work in terms of filling the filter.

 

[Lazy Daze]

I have filled the filter and turned the key on an off for an hour now, still no luck. Do I just need to keep turning the key on and off? I'm running out of ideas!

Should have filled within just a minute or two. Has anything else been changed/messed with? Is the kill switch in the run position? Engine obviously won't start, but the fuel pump won't activate either.

 

[TexasA&M]

pump is running like it always has (when first turning key on). Engine will run when shooting gas straight into the throttle body. This is an MPI boat, which is making this more of a hassle.

I've changed this filter twice before without filling it and eventually it has always started. Not sure what is different about this time. I'm starting to wonder if the filter is fubar'd (I've bought a new oil filter that doesn't flow before, so it isn't completely unheard of).

 

[testlab]

Take the filter off again and look to see if there is fuel in it. Since you put it on empty if there is fuel in it then at least the pump is able to draw fuel from the tank and through the lines. If there is no fuel or very little then you have a problem with fuel getting to the filter or an air leak.

Check the gasket face on the new filter. Smear a finger dipped in engine oil around the seal. Check the face of the filter housing for a bit of old o ring or seal.

I have always treated petrol filters like diesel ones and fill them before fitting. A few KOKO cycles to get the pressure back up and to purge the return lines and no trouble restarting. If I have had the fuel cooler out then I may remove the filter and refill it after 2 KOKO cycles.

If the filter is put on empty and the system has emptied somewhat, and someone please correct me if I am wrong, the air winds up circulating through the fuel system for quite some time before it is purged. This doesn't matter so much in cars because the return fuel line goes back to the tank where in boats it goes into the filter. I assume it is supposed to purge through the injectors but from early experience that can take ages since I generally don't like cranking an engine for more than 10 or 15 seconds.

 

[Gunn]

Turning the key off and on has never worked for me, whether it be when I have experienced vapor lock or the first time I put on an empty filter. Just take the dang filter off and fill it! When you remove it I bet it will be only partially full. I don't think using the key works as the line is essentially vapor locked by the trapped air in the (empty) fuel filter. Nothing is going to purge that air...unless you use the Schrader valve on the fuel rail or...remove the filter and fill it by hand.

What has taken you hours to solve can probably be resolved in just a minute or two.

 

[Lazy Daze]

I've never had the KO procedure not work for me... And this is with many, many different boats - not just my own. Now, why it doesn't seem to work for others, well, I'm not sure. I don't doubt them when they say it didn't work - just can't explain it since I've never come across the problem.

Either way, next step is definitely to verify if fuel is in the filter. If you don't do this already (in addition to rags) cut the bottom 2"-3" off an old antifreeze jug or 1-gallon milk jug. Start the filter removal (just enough to break it free where you can do the rest by hand, but not enough to leak fuel) and then slip the container underneath and finish. Drop the filter into the container and tilt the filter over to dribble out some fuel (if it's full) if you want to remove the filter completely.

 

[TexasA&M]

Turning the key off and on has never worked for me, whether it be when I have experienced vapor lock or the first time I put on an empty filter. Just take the dang filter off and fill it! When you remove it I bet it will be only partially full. I don't think using the key works as the line is essentially vapor locked by the trapped air in the (empty) fuel filter. Nothing is going to purge that air...unless you use the Schrader valve on the fuel rail or...remove the filter and fill it by hand.

What has taken you hours to solve can probably be resolved in just a minute or two.

As I said about 4 posts ago, I had already filled the filter and the boat would still not start. I filled the filter completely up and tried starting the boat for a solid hour to no avail. Please read all of the posts before being a smarta$$.

Anyhow, I finally got her running yesterday bout 7pm. Didn't do anything other than turn the key. I jumped in after it had been sitting for about an hour and it started right up like it always has. No idea what was going on, but I'll never put an empty filter on the boat again!

Thanks for all of the help!

 

[src]

As I said about 4 posts ago, I have already filled the filter and the boat would still not start. I filled the filter completely up and tried starting the boat for a solid hour to no avail. Please read all of the posts before being a smarta$$.

Jeez - if you'll read the other posts that people made in response to you, you'll see that ALL of them missed the fact that you filled the filter. No need to get pissy over a simple mistake. Dial back the rage a bit.

 

[TexasA&M]

I noticed those as well, but couldn't quote them all!

 

[Gunn]

Thanks for picking mine to quote, I appreciate it. I apologize for missing that fact, and I did miss it.

In any case, the cause still applies. You air locked the line between the fuel filter and the fuel rail. When trying to run the boat with an empty fuel filter, the remaining fuel in the line probably let the boat start and run initially for 30 seconds or so. Then the fuel void hit the injectors and it stalled and would't restart. You then filled the fuel filter but that air lock is difficult to overcome. If you had a fuel pressure gauge, purging the fuel rail using the Schrader valve would have made quick business of getting fuel to the injectors. Otherwise, the key on/off method that Dennis recommended was your only recourse. I guess an hour + one more try was the trick.

I think this will be a much easier chore next year.

 

[TexasA&M]

Agreed. I will never ever put an empty filter on there again! I was thinking that there was some type of purge valve on the fuel rails, but I couldn't find them (I didn't look THAT hard). Good to know that they are there though, just in case.