1999 Mercury 200 EFI - intermitent problem

[roliver007]

I have a 1999 Mercury 200 EFI. I have had this problem for the last 18 months occasionally at first (maybe once every 2-3 fishing trips), but now happens at least once every bass tournament.

At some point in the day when I start the motor it seems to be running rough (maybe running on less than 6 cylinders). It will idle, but when I step on the gas it bogs down at about 1500 -1700 RPM and thats all it will do. Sometimes all I have to do to get it to run is turn it off and restart and it might br fine. Sometimes it seems if I let it set for say 30 minutes it will run. I have tried just pumping the gas bulb etc, but it doesn't seem to matter. It never cuts out once I'm on plane and runs just as good as ever if it runs. It has done this before getting it off the trailer, but seems to be worse after the first long run of the day ( a "long run" may be 10 minutes). Most of the time after it does it once it seems to be OK the rest of the day.

The local dealer has checked it out several times and finds nothing wrong. They once changed the stator (sp? I think) and this week took it out and ran it (of course it ran fine while he had it) so he tried changing one of the power packs (I think it is called something else), but it still wouldn't run once this last Saturday. His plan is to swap the new power pack to the other side next.

Anybody have any ideas? Very frustrating.

 

[j_martin]

Re: 1999 Mercury 200 EFI - intermitent problem

I have a 1999 Mercury 200 EFI. I have had this problem for the last 18 months occasionally at first (maybe once every 2-3 fishing trips), but now happens at least once every bass tournament.

At some point in the day when I start the motor it seems to be running rough (maybe running on less than 6 cylinders). It will idle, but when I step on the gas it bogs down at about 1500 -1700 RPM and thats all it will do. Sometimes all I have to do to get it to run is turn it off and restart and it might br fine. Sometimes it seems if I let it set for say 30 minutes it will run. I have tried just pumping the gas bulb etc, but it doesn't seem to matter. It never cuts out once I'm on plane and runs just as good as ever if it runs. It has done this before getting it off the trailer, but seems to be worse after the first long run of the day ( a "long run" may be 10 minutes). Most of the time after it does it once it seems to be OK the rest of the day.

The local dealer has checked it out several times and finds nothing wrong. They once changed the stator (sp? I think) and this week took it out and ran it (of course it ran fine while he had it) so he tried changing one of the power packs (I think it is called something else), but it still wouldn't run once this last Saturday. His plan is to swap the new power pack to the other side next.

Anybody have any ideas? Very frustrating.

I wonder if you might have a leakage to ground in the kill circuit. Maybe disconnect it at the power packs, and test it back through the harness with a sensitive ohmmeter.

hope it helps
John

 

[npr0520]

Re: 1999 Mercury 200 EFI - intermitent problem

I had a intermittent problem with my 2002 merc 115 EFI - not exactly like yours but very frustrating. The engine would cut out for a second and the boat would lurch and then take off again when the engine recovered. This would happen about once in every five times I was out - for about a year. It got progressively worse and more frustrating - this summer it finally went solid. It turned out to be a short in the wiring harness where it passes behind the intake silencer and into the engine control module. It was shorting on the upper right hand bolt head that secures the module. I imagine as the rub got worse and the wire was further exposed it was finally enough to short the fuse. One thing about that harness; it passes through a very tight space and there is no corrugated tube protecting it over that bolt which is sharp. There is a temp sensor that branches out and that would be the only reason I could think of as to why it is not protected. I am not sure if the 200hp EFI has the same set up but it might be worth a check if it does.

 

[Ed R]

Re: 1999 Mercury 200 EFI - intermitent problem

Ed r here! Merc EFI ! motor has a filter on high pressure pump in the VST tank , and 6 screen filters on injecters that seem to be always over looked . After awhile, the bog, gets worse an worse. Or TPI out of adjustment, motor runing too cold !

 

[Des Barnes]

Re: 1999 Mercury 200 EFI - intermitent problem

I have the same engine and am currently dealing with the same problem. It appears now that the propeller when reworked was not to spec. but more on that later.

When my mechanic checked the engine we found that the check valve at the bottom of tube leading from the oil resivoir had failed. This clear tube should be filled with just oil (almost black) however it was clear (gasoline).

The gasoline was pushing itself up the tube to the oil resivoir, once the engine did start, this would pass back down, but the mixture would be never correct.

Changing the valve corrected the rough running on start up and idle.

The engine however continues to bog and not get out of the hole efficiently. But I had the propeller redone and now notice, comparing it to a new prop that he never put any cup back into the blade. I'll be testing some new props tomorrow.

 

[Des Barnes]

Re: 1999 Mercury 200 EFI - intermitent problem

Checked out several props yesterday. One was a trophy exact same model as mine that had not been reworked. It performed worse. The boat would not come out of the hole.

Tried a Trophy plus 25 pitch, it performed the same as my original. The engine does not deliver the thrust to get out of the hole. Sit at between 2500 and 3000 RPM, bogging (not blowing out).

In 15 to 30 seconds it will get up enough speed to get out of the hole and on WOT it get to between 4500 and 5500, speeds between 40 and 50 mph.

Every time I stop and retry it is a little different, sometimes worse sometimes better. Back to the mechanic this week, I assume it must be a control module or some electrical problem.

Any ideas?

Des

 

[zmkfisho]

Re: 1999 Mercury 200 EFI - intermitent problem

I have a 1999 Mercury 200 EFI. I have had this problem for the last 18 months occasionally at first (maybe once every 2-3 fishing trips), but now happens at least once every bass tournament.

At some point in the day when I start the motor it seems to be running rough (maybe running on less than 6 cylinders). It will idle, but when I step on the gas it bogs down at about 1500 -1700 RPM and thats all it will do. Sometimes all I have to do to get it to run is turn it off and restart and it might br fine. Sometimes it seems if I let it set for say 30 minutes it will run. I have tried just pumping the gas bulb etc, but it doesn't seem to matter. It never cuts out once I'm on plane and runs just as good as ever if it runs. It has done this before getting it off the trailer, but seems to be worse after the first long run of the day ( a "long run" may be 10 minutes). Most of the time after it does it once it seems to be OK the rest of the day.

The local dealer has checked it out several times and finds nothing wrong. They once changed the stator (sp? I think) and this week took it out and ran it (of course it ran fine while he had it) so he tried changing one of the power packs (I think it is called something else), but it still wouldn't run once this last Saturday. His plan is to swap the new power pack to the other side next.

Anybody have any ideas? Very frustrating.

Hi Roliver...did you ever get to the bottom of what was causing the bog down issue? Would you mind posting an update?

I have a 1999 200EFI XL Saltwater series. Have owned it since new and now has some 170hrs run time. I am now intermittently experiencing the same bog down in the 1500-1700RPM range. Even if I push down on throttle all the way - there seems to be no response and the motor chugs along 1500-1700RPMs. If I cut back the throttle and re-apply it either stalls or takes off and runs normally. Very frustrating, and unsettling as I frequently trawl offshore near headlands etc.

Looking forward to an update.