200 EFI Mercury...Fixed!!

[blazer81.6]

I was referred to this forum by a friend and couldn't be more pleased to be a member. In under a week I've been able to troubleshoot and resolve the fuel issue I had with my Mercury. After checking compression, ignition and psi on manifold check valve I went with an alternative fuel tank and cleaned my water seperator filter. I ran a hose from the fuel tank into the inlet of the fuel pump, she fired right up without any hesitation. I'm guessing that a new syhpon valve with solve my problem. Thanks to all for previous input and to iboats.com, very, very appreciative.






I currently own a 1999 Merc. EFI and am experiencing mechanical problems. The motor starts easily, idles well and revs smoothly. After a quick rev the engine stalls. The motor will idle smoothly for approximately 10 seconds then repeats the same failure but again starts. I have tackled some mechanical problems in the past with other rigs but really don't know where to start, imagining it could be several things,i.e fuel/water seperator, fuel pump, final filter, fuel regulator, fuel primer. Last summer, when this mechanical failure began, i was traveling down the lake (65-70mph) and it shut down quickly. It was like you reached over turned the ignition off. If this problem sounds familiar with anyone else please post. Thank you in advance for any possible insight.

P.S Compression 113-115 psi on all 6.

 

[CharlieB]

Re: 200 EFI Mercury...Fuel Problem?

Re: 200 EFI Mercury...Fuel Problem?

You've pretty much ruled out a mechanical problem by testing the compression, now you have to test to determine if it is a fuel problem with the EFI or an ignition problem.

To K.I.S.S., start with the ignition, remove the spark plugs again, attach an adjustable gap spark testor to each of the plug wires, set the gap at 7/16 inch, crank the motor and observe the spark. Hopefully you will get a very crisp bright blue arc. Advance the throttle to WOT and retest spark to be sure that you do not have a problem with broken wires between the timer base and the ignition moodule, killling spark as the timing is advance with the throttle.

If the ignition passes both at idle timing and WOT timing then it is time to start cleaning the fuel system and testing fuel pressure.

 

[Faztbullet]

Re: 200 EFI Mercury...Fuel Problem?

Re: 200 EFI Mercury...Fuel Problem?

Do you have a battery guage and was engine overcharging? Is primer bulb staying firm?

 

[blazer81.6]

Re: 200 EFI Mercury...Fuel Problem?

Re: 200 EFI Mercury...Fuel Problem?

Thanks for the advice, sounds like I'll start with the ignition system. I can trouble shoot that problem without any cost and sounds like a great place to start. Blazer, thanks for the reply but it doesn't have a charging gauge. I would like to add one more decription about this ongoing problem. Early last summer the motor did the exact same thing as it currently is doing. I was traveling down the lake and the motor shut off abruptly, would start back and plane for just a second then shut back down. I had about 1/4 tank in each side but thougt my gauges may be inaccurate. I filled up and the boat ran fine afterwards until now. I've got about 1/4 in each side (checked the tanks to make sure) which makes me think that it could be fault in the fuel pump. I'll start with the ignition and go from there. Thanks so much for replying.

 

[mca1634]

Re: 200 EFI Mercury...Fuel Problem?

Re: 200 EFI Mercury...Fuel Problem?

Ive had a similiar problem for the past two weeks. Are your fuel lines grey? If so, the inside of them are deteriorating. whether it's the ethenol of from just sitting a long period I had the same exact problem. I have a 2000 200 efi. Just bought it 7 months ago and i'm pretty sure it sat for a while. Check if there is a varnish looking material in you filters. if so change your lines and flush motor.

 

[blazer81.6]

Re: 200 EFI Mercury...Fuel Problem?

Re: 200 EFI Mercury...Fuel Problem?

Grey lines, yes. What filter are you referring to, water seperator?

 

[mca1634]

Re: 200 EFI Mercury...Fuel Problem?

Re: 200 EFI Mercury...Fuel Problem?

if you have a water separator filter and definetely check you fuel filter. if there is debri in it then you should probably go further than that. vst tank and then injectors

 

[blazer81.6]

Re: 200 EFI Mercury...Fuel Problem?

Re: 200 EFI Mercury...Fuel Problem?

I've verified that spark, compression are reading satisfactory. I also got the opportunity to check the pressure port beside of the fuel pump this evening. Its reading around 41psi. Where from here? I appreciate the previous assistance.

 

[Faztbullet]

Re: 200 EFI Mercury...Fuel Problem?

Re: 200 EFI Mercury...Fuel Problem?

Need some more information. Do you have a battery guage and is it overcharging? Is primer bulb still hard or do you have to pump it back up? Several items can cause the problem your are describing. The primary fuel pump diaphram bad, rectifier/s bad ,stator bad, tps out of adjustment or bad,bad fuel pump or clogged screen, failing driver board in ecu, is fuel pressure steady or jumping about while running?