My Evinrude Ficht 200 fuel injected, while running above 200 RPM has no problems but when idling the no oil alarm goes off and there is plenty of oil in the tank.

not sure but here is the parts breakdown for the whole motor. You should be able to locate what you need from here.
https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=2002&hp=75&model=E75FPLSNF
hope this helps you.

The low oil sensor is not "seeing" the oil in the tank...(mine does this when I crank it,, the low oil light stays on).. It uses plenty of oil,,I quit worrying..- -don't feel like taking the oil system apart..
Get one of these.. I have one for every outboard I ever owned..they DO come in handy...

Mercury Outboard Manuals by Seloc 1965 2014

It's a safety issue. The computer is trying to save your engine and transmission. If there isn't a light, there still could be a code. It would be in history codes. It takes a scanner to retrieve them. Unless your a race car driver or doing 200 MPH all the time. The RPM's shouldn't stay at 4000 RPM's.

You don't say if the engine is carb or fuel injected.
If it has a carb, it could be sticking linkage for the fast idle to the choke.
If it is fuel injected it could be a faulty idle air control valve.
Or it could be something holding the throttle open like a binding cable.

Check out related help links to troubleshoot these problem:----Click the link below:---Idles Fine but RPM jumps in drive mode? http://technoanswers.blogspot.in/2012/07/idles-fine-but-rpm-jumps-in-drive-mode.html
---------Mitsubishi Lancer rpm needle bounces? http://technoanswers.blogspot.in/2012/02/mitsubishi-lancer-rpm-needle-bounces.html
--------How to adjust rpm on 2009 dodge charger SRT8?

http://schematicsdiagram.blogspot.com/2011/12/how-to-adjust-rpm-on-2009-dodge-charger.html
---------
Engine cuts out at 3000 RPM? http://schematicsdiagram.blogspot.com/2011/12/engine-cuts-out-at-3000-rpm.html

---------

Cold start problem and vehicle shudder around 2500 to 3500 rpms
http://repairhelpcenter.blogspot.com/2012/10/cold-start-problem-and-vehicle-shudder.html

---------
High rpm in neutral? Inconsistant high RPM in neutral? http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html

-----------
Jetski Sputters and Low RPM? http://whatisbyme.blogspot.in/2012/07/jetski-sputters-and-low-rpm.html

--------
Fuel Injection Problem And RPM suddenly increases http://whatisbyme.blogspot.in/2012/07/fuel-injection-problem-and-rpm-suddenly.html

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2005 Toyota Highlander: Engine runs hard RPM below 3000? http://whatisbyme.blogspot.in/2012/05/2005-toyota-highlander-engine-runs-hard.html

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1987 Toyota Camry: RPM Drops going Up hills? http://whatisbyme.blogspot.in/2012/05/1987-toyota-camry-rpm-drops-going-up.html

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Cruise Control stops working, Excessive cranks to start the engine and RPM goes max 2500 http://whoisbyme.blogspot.in/2012/07/cruise-control-stops-workingexcessive.html

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1990 Toyota 4Runner: Engine cuts off when reaches 2000 RPM?

http://whatisbyme.blogspot.in/2012/05/1990-toyota-4runner-engine-cuts-off.html

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1999 Toyota Camry: Erratic stalling and high engine RPM at idle?

http://whatisbyme.blogspot.in/2012/05/1999-toyota-camry-erratic-stalling-and.html

---------
1995 Toyota LS: Misfire at idle or low RPM http://whatisbyme.blogspot.in/2012/04/1995-toyota-ls-misfire-at-idle-or-low.html

-----------
Lexus RX: Tapping noise under Valve Cover At Low RPM? http://technoanswers.blogspot.in/2012/04/lexus-rx-tapping-noise-under-valve.html

----------
These will help.
Thanks.

Check out related help links to troubleshoot these problem:----Click the link below:---Idles Fine but RPM jumps in drive mode?http://technoanswers.blogspot.in/2012/07/idles-fine-but-rpm-jumps-in-drive-mode.html
---------Mitsubishi Lancer rpm needle bounces?http://technoanswers.blogspot.in/2012/02/mitsubishi-lancer-rpm-needle-bounces.html
--------How to adjust rpm on 2009 dodge charger SRT8?

http://schematicsdiagram.blogspot.com/2011/12/how-to-adjust-rpm-on-2009-dodge-charger.html
---------
Engine cuts out at 3000 RPM?http://schematicsdiagram.blogspot.com/2011/12/engine-cuts-out-at-3000-rpm.html

---------

Cold start problem and vehicle shudder around 2500 to 3500 rpms
http://repairhelpcenter.blogspot.com/2012/10/cold-start-problem-and-vehicle-shudder.html

---------
High rpm in neutral? Inconsistant high RPM in neutral?http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html

-----------
Jetski Sputters and Low RPM? http://whatisbyme.blogspot.in/2012/07/jetski-sputters-and-low-rpm.html

--------
Fuel Injection Problem And RPM suddenly increaseshttp://whatisbyme.blogspot.in/2012/07/fuel-injection-problem-and-rpm-suddenly.html

----------
2005 Toyota Highlander: Engine runs hard RPM below 3000?http://whatisbyme.blogspot.in/2012/05/2005-toyota-highlander-engine-runs-hard.html

---------
1987 Toyota Camry: RPM Drops going Up hills?http://whatisbyme.blogspot.in/2012/05/1987-toyota-camry-rpm-drops-going-up.html

-----------
Cruise Control stops working, Excessive cranks to start the engine and RPM goes max 2500 http://whoisbyme.blogspot.in/2012/07/cruise-control-stops-workingexcessive.html

----------
1990 Toyota 4Runner: Engine cuts off when reaches 2000 RPM?

http://whatisbyme.blogspot.in/2012/05/1990-toyota-4runner-engine-cuts-off.html

------------
1999 Toyota Camry: Erratic stalling and high engine RPM at idle?

http://whatisbyme.blogspot.in/2012/05/1999-toyota-camry-erratic-stalling-and.html

---------
1995 Toyota LS: Misfire at idle or low RPMhttp://whatisbyme.blogspot.in/2012/04/1995-toyota-ls-misfire-at-idle-or-low.html

-----------
Lexus RX: Tapping noise under Valve Cover At Low RPM?http://technoanswers.blogspot.in/2012/04/lexus-rx-tapping-noise-under-valve.html

----------
These will help.
Thanks.

Hook up a fuel pressure tester start and let run until dies and check pressure if plenty of pre.ssure If this is a carberated engine tune your air and fuel mixture jets located in front bottom of the carb.., hook up vacuum and set to your hightest reading and then set your idle screw to prefered idle which is around 8 RPM If this is a injected system hook up a fuel pressure guage and start engine and let it run until it stops keep an eye on pressure to see if the pressure drops or stops if so replace fuel ****

200 rpm's will diffenetly create a very low oil pressure signal. I can not see how your engine will run at 200 rpm's neither. check the voltage output of your altenator for if its bad this will cause a problem such as yours

Rough idling commonly comes from defective components of the electronic fuel injection system. You may start with fine tune adjustment of the idling speed using the idling speed adjustment port just above the TP sensor. If it will not help, try loosening the bolt of TP sensor, change the mounting angle and observe for any improvement. If doing this will not work, replace the TP sensor. If still the problem is present try cleaning or replacing the idle air control valve. The one with hose connection to the air intake pipe. If still it will not work, try replacing the MAF sensor just after the air filter. The last thing you may do if all of the things above will fail, have someone check your ECM.

Cleaning the PCV (positive crankcase ventilation) valve may help too. Why not start with this activity.