1996 Mercury 200 EFI stalls randomly at 3000 RPM

[imported_bman]

I have a 1996 200EFI Merc than runs great (most of the time). Several times this summer, it has died while cruising at speeds anywhere in the range of 2000 to 4000 RPM. The engine just dies very suddenly. I can restart it easily. Sometimes it will happen again within a minute or two, and sometimes it will run for an hour or more without a repeat. The primer bulb always seems to be firm. Any suggestions?

 

[mistylady2]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

I have a 1996 200EFI Merc than runs great (most of the time). Several times this summer, it has died while cruising at speeds anywhere in the range of 2000 to 4000 RPM. The engine just dies very suddenly. I can restart it easily. Sometimes it will happen again within a minute or two, and sometimes it will run for an hour or more without a repeat. The primer bulb always seems to be firm. Any suggestions?

I have a 2001 merc 200efi, had the same problem. solution: wire harness. open the pins a little reconnect and tape securely. Its located on the engine block. The tell tale on mine was when it died, and you turned the key , it would not always turn the starter. hopes this helps.

mistylady2

 

[imported_bman]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

Thanks very much for the tip. I pulled the hood on the weekend, and searched for any obvious wiring problems. I found a loose screw on a ground terminal with 3 or 4 ground wires on it. I tightened the screw, hoping that it would solve the problem. Next trip out, the problem re-occured.
Before it stalled once, I could hear that the engine was running rough, and it hesitated immediately before it stalled. This is the first time that I noticed any signs before a sudden stop.
So I followed your advice. The connector that I opened was a bayonet style. (round, push with a quarter turn to connect). There are about 20 pins. I cleaned the connector with a spray contact cleaner, and pinched the end of each pin with needle nose plyers, so that each pin was ovalled a bit at the tip. This increased the insertion resistance when the connector was assembled. Then I taped securely togeter.
So far I have only taken it out for a short test run, so it is too early to say whether the problem is solved.
I'm keeping my fingers crossed.

 

[heybaylor]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

I have/had the same problem. 96 efi 200 shutting down @3-4k..starts right up .vapor seperator full./bulb hard
:/.
I have spead the pins on the ecu connector .
One run so far ..no problems ..also the bogging at cruise seems to have gone away ...
another long run to come today ..time will tell

 

[imported_bman]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

Well, my work on the wire harness connector did not help. I used the boat a few times over the last week, always with the same problem, only worse now.
Once again, I am seeing the motor die suddenly at engine speeds of 2500 RPM an up.
But the problem is much worse now. The engine starts fine, but when I start out, it dies as I am accelerating while it is still cold. It seems fine up to about 2500 RPM under load, but after that, it tends to stall. Also, when at an idle, I can rev it to about 3200 RPM. If I increase the fast-idle lever to the max, the engine sticks at 3200 RPM and eventually dies.
Once the engine warms up, it accelerates fine, but stalls spontaeously at crusing speeds.

I gettng frustrated and will probably take it to a pro shortly.

 

[heybaylor]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

ok .., I also had a dying problem...a piece of debris was in the seperator seat...evey once in a while the seperator would run dry ..it was on top where the fuel line attaches ..
drain your seperator ,pull off fuel line from top of seperator
then blow low pressure air in the drain hole .
idea being that the air will clear the neadle seat ..then pump a little gas from the bulb just before you attach the fuel line .
If you want to pull the top of seperator be advised it has a $ 35.00 'o' ring and is is not ..reusable..
best way to really tell what is going on is to attach a fuel pressure guage to the regulator ..then you will know if indeed you are running out of gas , or it is something else..it should hold aproxx 30-35 pounds all the time...
if not ..then its either injector pump , or cpu power ..
if it holds then check /clean your injectors

 

[Dougindixie]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

Mine is doing the exact same thing and the dealer has tried, in vain, to correct this. I am at my witt's end having swapped out nearly every electrical component on it. It has never left me stranded but I have had to idle 12 miles back to the ramp on more than one occasion. Fuel? Electrical? Any other suggestions?

 

[oldute]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

Hi from Perth, Australia.
I have just replaced my underfloor tank and first trip out mine was doing the same thing as you guys are describing. Running fine for 3-5 minutes than a sudden drop of rev's. When it suddenly drops, I back the throttle back to neutral and it usually stalls, then I start it again & it starts no problem, then of it goes fine again for another 3-5 minutes. After this happened about 5 times to me, I decided to try it slower and it kept going no probs which made me think maybe I have a slight kink in the fuel line under the floor from installing the new tank thus restricting the flow of fuel. It will be hard for me to see if this is the case as the tank is almost full but hopefully I'll try and find out & let you know. This is the only thing I can think of because it has always run fine until I changed the tank. Does anyone think this is possible? When it dropped revs I quickly checked the fuel bulb and it wasnt sucked in though.

 

[Dougindixie]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

It' possible but I'd be more inclined to believe its either the diaphram or a possible blockage in the line inside the cowling. Does the bulb stay hard?

 

[oldute]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

Yes mate, the bulb does stay hard.
The full story is earlier that morning I started the motor, no probs then it stalled & wouldnt start. I checked the bulb and it would squash in but stay in.
Took me a while to realise that it wasnt sucking petrol from my new tank properly. I tried pumping the bulb for at least an hour all up and occasionaly got it pressured up only to start the boat and have it idle for a minute & die again.
Ended up removing the floor hatch and feeling the hose at the back of the tank which was kinked, so I pushed the surplus hose through a cutout at the back unkinking it where it was kinked. This made the fuel bulb work properly again and the motor started & stayed running until rpm problem previously mentioned.
Bearing this in mind could anything have happened to the diaphraghm trying to pump fuel against a kinked hose??

 

[Dougindixie]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

That's very possible, all it takes is a small pinhole to mess it up. How old are the hoses?

 

[Faztbullet]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

Bypass the fuel pump driver in ecu and test, most likely you have a A7 or 14 box ecu (pos).

 

[bob232]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

I am having the same problem with a 2001 Mercury 250 EFI. Running at 2500 to 3500 RPM the engine cuts off like hitting a kill switch but starts up fine every time. Have replaced fuel pump, fuel filters, TPS sensor, adjust everything according to the manual was running great at the end of the season last year but now we have this problem again.

Any suggestions? Help!!!!

 

[Dougindixie]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

a local mechanic stripped all the "un-necessary" electronics off the motor which included the spark/timing advance, oil injection new fuel pump and lord knows what else but it run fine now. I have to mix my oil but I suspect the issue was in the fuel system the whole time. I'd be happy to put you in touch and you could talk with him. Hope this helps!

 

[bob232]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

Thanks for the input. One other thing that is happening is when I am running at 2800 RPM the motor throttles up by itself to about 3400 RPM and sthat is when it will shut down. Where is the mechanic located? I am in Maryland.

 

[Dougindixie]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

Mine didn't rev up and it would never quit completely. He is in Birmingham, Alabama.

 

[bob232]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

Well, Thanks for all the input. The problem was in the fuel line, I believe that there is problem with the gray mercury mariner fuel line, it looks like the inner lining dried up and broke apart. I took out the fuel-water filter seperator and cleaned it out. I had replaced all the filters last summer, so if any one has trouble, check the fuel-water seperator filter for any debri, then check to see if it is a gray fuel line and replace it. Also check to see if it is softer than some of your other fuel lines as it will tend to collapse and shut down the motor upon asking for more fuel.

I replaced the fuel line, took it out this weekend and it ran like a charm except for a rough idle at low rpms but at high rpm it is running like a champ and I am still working on this. I will keep you posted. If anyone has any ideas about a rough idle at low rpms I would appreciate the input.

Thanks!
Bob232

 

[Dougindixie]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

Great! I suspected the same with mine and have been told the gas we are forced to buy now breaks down the fuel lines. I am glad you have solved the problem and hope you have a good summer with it!

 

[Thoroughbred]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

Great! I suspected the same with mine and have been told the gas we are forced to buy now breaks down the fuel lines. I am glad you have solved the problem and hope you have a good summer with it!

It's the ethanol. I have been lucky so far not to have to use it but still add Startron to keep it from separating just in case. Ethanol will eat carb gaskets too so look out for that. Also if you have an old boat it will clean all of the varnish out of your system which can clog all sort of things. If you have to use ethanol gas you should also have a water separator as some mentioned.

 

[fishangler]

Re: 1996 Mercury 200 EFI stalls randomly at 3000 RPM

really would like the mechanics name im haveing same troubles but know my fuel pressure is dropping off.im inclined to think fuel pressue regulator but aint sure.149.99 is a big guess need a professional opinion and eyes.
just a note*the vapor seperator oring now sells for 48.00 and is not reusable
dont seperate unless you just have to.
i live in pell cty al