Fuel starving and hard starts

[Plan3]

I have a 2004 200hp ficht, that, after repairs to the alternator system in the EMM by DFI, would start fairly easily. But, a few moments later, would be difficult to re-start. My mechanic put his laptop on it and told me the only message he got, although no alarm went off, was "low oil pressure." Eventually, we changed the oil pump (both the uptake and the injector pump). While going through these actions I noticed the fuel line from the gas tank, just in front of the primer was broken. So, based on what I've learned on these forums, the motor had to be sucking air. Good, I've changed the fuel line and she's still hard to start after the initial start. I decide to check the fuel and oil line going to the motor at the cowling. I remove the retaining plate at the cowling entrance and discover that the oil line too is broken and was only held together by the pressure from this flat metal plate. So now, I've got new hoses properly clamped,
Yet the hard starting after the initial start. Plus, the priming bulb gets real hard. If I disconnect the fuel line just beyond the in-line filter--the one outside the motor-- and squeeze the primer real hard, after a while fuel spurts out freely. What I've noticed also is: the priming sound coming from the fuel pump on the motor disappears at times. When that happens, the motor will only swing and not catch, hiccup or nothing! The sound comes back, weak at first, then stronger, she starts hiccupping and eventually starts, but runs rough and has to be accelerated frequently to run, or will stall.
Am I having a fuel-starving situation? Are there residual air pockets in the system that started the hard-starting problem to begin with and that are still hampering the operation of the motor? The forum's help on this matter will be greatly appreciated.

 

[Fleetwin]

I would be looking at two things:

1. Fuel tank venting.
2. Anti siphon valve at the outlet of your fuel tank.


An easy check would be to try and start with a seperate (non boat) fuel source.

 

[jakedaawg]

Isn't there a fuel and water seperator on that under the cowling. It may even have a wire atttached to the bottom of that. I don't have the manual right in front of me.

 

[daselbee]

Are you saying that the fuel pump running sound comes and goes? The correct operation is that when key is turned ON, the fuel pump runs for 10 secs and then shuts off.
If this is NOT happening, for example, if the fuel pump runs sometimes, but not others, then you still have EMM problems.
The EMM controls fuel pump operation.

It would not surprise me at all if DFI sent back an EMM that still had a fault.

 

[jakedaawg]

I just reread the original post. If I am reading right you are saying if you disconnect the fuel line immediately after the exterior fuel/water separator and pump the bulb it is still difficult to get fuel to come out? It should take minimal effort to pump through that, almost like no resistance at all. I would check the entire ship side fuel system including looking for fuel lines that are collapsing internally under suction, anti-siphon valve, fuel tank pick up screen, bulb, filter etc.

If I read wrong or misunderstood-ignore what I just wrote.

 

[Plan3]

Thanks, Forum, especially to Fleetwin, jakedaawg, and daselbee, who chipped in quickly and gave practical, easy-to-follow advise. In putting it together so far, it seems likely that we've isolated the problem to a fuel situation; that holds even for the suggestion that the repaired EMM might be at fault for sending off-and-on messages to the fuel pump. I'm going through a "time-out," then will return to the project and work through the process step-by-step, keeping your collective advice in mind. I'll keep you posted on progress. Again, many thanks!

 

[Plan3]

Just an update on the "fuel-starved, hard starts" thread I started: I said I'd take a time out, while thanking the Forum for input. I had come to believe it was a fuel-related problem, especially with the Forum's input. So, now I would say cautiously, the problem is almost solved. I'm starting a bit easier, and quicker. The "but" is that, when the motor swings for a while and won't start, if I have the accelerator lever pushed all the way to full throttle while the fuel pump on the motor is priming--buzzing--, then when I click for start, I almost always get an immediate start. Then, I can throttle back and run the motor normally. Might this be a sign that the fuel pump is on its way out? Just a guess. If I'm totally off base and just wishful thinking, I'd appreciate a response! Again, thanks to the For the advice and suggestions!