97 200 EFI shuts down at idle and on plane; will restart

[Bobby8]

97 200 EFI OG 468620 on PII Basscat
2 weeks ago on first run of the day, ran 15 minutes; fished for an hour. Motor fired up twice and immediately shut down; then would not start at all. I replaced plugs (BU8H), primer bulb, fuel lines (3/8 to bulb-5/16 to motor-old lines were like new on inside), replaced fuel filter (no contaminates found), I rebuilt the low pressure fuel pump (no contaminants found), dropped the VST lower housing and it was clean. Went to lake and boat starts fine. Issue now is that motor shuts down on long idles and on plane-EVERY OTHER time motor is started. One time it runs fine, the next time it shuts down. I went to another dealer and got and installed another primer bulb-this one is a Yamaha. Motor is still shutting down as above. I have been priming bulb before each start. Bulb is soft after engine shuts down on its own. I looked through the service manual I got from Don. It says either high voltage or fuel delivery. I figure it must be something I replaced because the shut down issue started when I replaced the above. I cannot for the life of me figure out the cause. I have looked at all the connections and surrounding connections and all seem fine. Ran boat with ears today and did not see voltage above 14.5. I always hear the electric fuel pump when listened for. Sorry this is so long. Any help would be appreciated.

[heybaylor]

my 96 did this , more or less.(randomly just quit)
What fixed it was the engine main connector.
I cleaned ,tightened pins (spread pin slots with razorblade).
dielectric on pins and problem gone

[EuropeanAM]

+1

Also check the ECU connector to make sure it's retainer is fully locked, and snapped into it's retainer.

[Bobby8]

Thank you both for the input!! Will check out both now.

[Bobby8]

Just found that the gray coupler ring is split vertically on the female side of cannon plug on the ECM wiring harness. Number 18 on the ECM diagram (pg 3C-2). The connections were loose. Do I have to order the whole harness, just the cannon plug or can the gray coupler ring be ordered and installed separately? As a temp fix can I super glue the ring and reinforce with electrical tape? Thank you again for your time.

[JOE54]

190491 is p/n push together real good tape it tight and test run/ welcome

[Bobby8]

Thank you Joe for the advice and part number. Will try to get on a lake the next couple of evenings.

[Bobby8]

Well I ran the boat this afternoon and it shut down again on plane. It started right up after priming the bulb. Once on plane again I watched the battery gauge closely. Between 3,000 and 4,000 rpms it was pegged out past 16. I assumed voltage regulator(s) bad. Once home I found where the lower regulator's wires connect to the engine' s wires beside the upper regulator, the plastic sleeves are melted some and are a brown color. I will try to find a pair of regulators around here tomorrow. Also on the way home I bought a new cranking battery as I had only a 625 MCA installed. Any other ideas for me to check? As always I appreciate your time and knowledge.

[JOE54]

would replace both regs with new oem parts/ batt sounds lil small I don't put anything less than 1000 on v6 better to have too much than not enough

[EuropeanAM]

would replace both regs with new oem parts/ batt sounds lil small I don't put anything less than 1000 on v6 better to have too much than not enough

+1

Also, REPLACE any discolored, melted, or damaged Bullet Connectors for the harness-side at the regulators (in addition to replacing both regulators with new, OEM Mercury Components).

[Bobby8]

Thank y'all again for the time and advice. Purchased 2 Merc regulators today. New ones have a 30 amp fuse which is different. Both are installed less 2 connectors that I must find somewhere tomorrow. New 1000 battery is in place patiently waiting. Will try to run boat this weekend. Wish me luck. Y'all are good folks offering your expertise as you do.

[JOE54]

good luck BOB

[Bobby8]

Well, ran my boat at the lake and had the same issues. Put boat in the water by by the time I had parked the trailer and got back, motor had shut down. Bulb was soft. Primed bulb and motor started on 3rd try. Ran around the lake for 5 minutes or so. Fished for 40 minutes. Primed bulb. Motor would not start. After 5 minutes it started. Immediately after getting on plane the motor shut down in a way like it ran out of fuel-sputtered and shut down. Build was soft, primed it and it started on first try. Ran a while then fished for 30 minutes. Primed bulb, got boat on plane then it shut down like the kill switch had been tripped. This same thing happened after the next start. Frustrated I headed home. Every time the engine shuts down on its own, the bulb is soft- is this normal? Votage gauge after the regulator change was rock steady at 14 on plane. I am at a loss. I never had an issue with the engine shutting down until I changed the plugs, fuel lines, primer bulb and rebuilt the low pressure fuel pump. Seems like one of those should be the culprit but I don't know. Guess I am going to go to a shop. Sorry this is so long. Any ideas would be appreciated.

[Reel Life]

Before you give up, get a pressure gage (0- 60 or 100) psi with a hose and fitting for a schrader valve and attach it to the schrader valve on the VST. Then run the boat and monitor your fuel pressure to see if it goes down. Your system should run at about 35 psi. You may have a pump driver crapping out in your ECU.

[Bobby8]

Thanks Mark. I will do that. A question, if the driver was going out would the shutting down problem be an intermittent one? Thank you again.

[EuropeanAM]

It could be intermittent.

Personally, I would recommend attaching a PORTABLE fuel tank, with it's own line and primer bulb DIRECTLY to the engine, and then run the engine to see if the problem continues (or ceases).

Simple way to determine if it's a BOAT fuel system supply problem, or something inside the engine cowling.

[Bassman469]

Your symptoms sound very similar to those I had on my 200 EFI. I followed Don's advice and eliminated the fuel system first. My problem ended up being my ECM. Sent it off to get fixed and haven't had a single issue since.

[Rich Z]

A $5 30a head lamp relay should fix your problem in the ecu with fuel pump driver circuit. I just don't know how to wire it.

[Takeum]

NOt sure if you fixed your problem yet,,, but my 97 200 efi did something very similar as far as the shutting off at certain rooms or n plane,,, seems as if I tried to go past 3800 rpm the motor would starve, then shut off for 15 minutes,,, after spchecking all the fuel lines from tank to bulb,,, I decided to try and disconnect the lines from fuel filter to VST and found the issue there,,, The fuel lines were so clogged from inside out, I couldn't even blow threw the lines...So I replaced All the motor fuel lines I could find that looked bad and it solved the problem,,

[Mark Wendler]

I never had an issue with the engine shutting down until I changed the plugs, fuel lines, primer bulb and rebuilt the low pressure fuel pump. Seems like one of those should be the culprit but I don't know.

I recently rebuilt my Low Pressure Pump, and experienced symptoms somewhat similar to what you are experiencing. But, mine was most pronounced when idling for a distance. It would flat run out of fuel and lose prime. It turned out to be a mistake of mine by using the Sierra (junk) brand kit. I rebuilt it again using a Mercury kit, problem solved.