Bass_Fanatic Posted February 1, 2011 Posted February 1, 2011 I have got a 1995 Mariner Magnum 200 EFI motor that is giving me problems. The ECU is not sending a signal to my fuel pump to tell it when to turn on and off while the motor is running. My local mechanic told me it needed a brand new computer, which is $1800, but I was wondering if you guys knew which part this was. I found some Mariner ECUs on ebay for alot cheaper, but Im not sure if they will fit and also I am scared that they will not work. I ran a wire around the ECU to a swtich and to the fuel pump and I can get it to crank, but it is a pain to keep it running because I have to continously cut the switch on and off. Buying a new ECU is out of the question, the wife has made that clear >, but I am hoping someone knows of one taht I can get for cheap. Thanks! Quote
Super User bilgerat Posted February 1, 2011 Super User Posted February 1, 2011 First, are you 100% sure the ecu is the problem ? When you buy an electrical item, you own it whether it fixes the problem or not. Most parts sellers state plainly "No returns on electrical items" The ecu's I deal with on marine diesels have to be programmed to the engine serial #. There is no such thing as buying one off the shelf ready to go. Putting the wrong ecu on with different inputs and outputs could lead to big trouble. I don't know if outboards are this way but it would pay to check into it thoroughly. Quote
Bass_Fanatic Posted February 1, 2011 Author Posted February 1, 2011 Im positive its the ECU. I have been researching a bit and have found many others with the same problem I am having. Without my ground going to the fuel pump, it will not turn on. Apparently, the ECU got loose and created an arch to the pin for the fuel pump and damaged it. Everything else runs fine and dandy, but a motor cant run without gas. If I buy an ECU off of another 95 200 hp Mariner EFI, wouldn't it work? ALso, would it hurt if I somehow went around the ECU for the fuel pump for good? Quote
fishn hard Posted February 1, 2011 Posted February 1, 2011 you need the A17 computer for that motor but you can wire the pump to a switch and YOU DO NOT NEED TO TURN THE SWITCH ON AND OFF your regulator will take care of the fuel pressure i took all of my vst tank junk off and put it in the trash i put the pump in the boat on a switch and relay and it idles better. but if you want a computer for your motor let me know i can get you a good one that you can trust Quote
Bass_Fanatic Posted February 1, 2011 Author Posted February 1, 2011 OK Im not very familiar with outboard motor parts, so what is the VST you are talking about? Also, the way I have it rigged right now with the pump constantly running will not hurt anything? My mechanic told me it isn't good and the pump has to be ran through the ECU. Quote
fishn hard Posted February 1, 2011 Posted February 1, 2011 The VST tank is the can that you see on the port side of the motor that holds your fuel pump it is a vapor separator tank VST. Any time you send your computer to brucatos or rapair they will tell you to put the pump on a switch the vst tank is a poor design from merc it takes all of the unused fuel and returns it to the vst tank to be run through the pump first to feed the injectors witch means your allways burning hot fuel and we all know that means less power cold fuel means more power and with the pump turning off and on is anther bad design on mercs part think of it like this when your running down the lake and that pump is on off on off the pressure is going up and down and there is 3 things that kill a motor 1 lack of oil 2 over heat 3 motor running lean and 90 percent of the time a lean condition kills a out board Quote
Bass_Fanatic Posted February 1, 2011 Author Posted February 1, 2011 Thanks for all your help... So the way I have it rigged around the ECU will not hurt anything? If the pump is constantly running, even with the VST, it will not hurt the motor? Quote
fishn hard Posted February 1, 2011 Posted February 1, 2011 it will not hurt but wire the the on off switch with a regulator straight from the battery and if you ever want to get rid of that vst tank let me know and ill walk you through it and one more thing that computer you have has a lean spot at 5000rpms to 5300rpms so don't hold it there for long Quote
Bass_Fanatic Posted February 1, 2011 Author Posted February 1, 2011 Ok I appreciate it. What do you mean by a lean spot between 5-5.3k RPM? Quote
Bass_Fanatic Posted February 1, 2011 Author Posted February 1, 2011 I found an ECU part # 824003 8, where as mine is 824003 1...would that part work or not? Quote
fishn hard Posted February 1, 2011 Posted February 1, 2011 On the A17 box the computer tells the motor to go lean witch means more air less fuel as Told by Tony Brucato he is the best computer man in the world he makes a after market computer (PCU) programmable Control Unit witch i have on my motor and all of mercury 2.5 race motors come with his computer not there's.so whats that tell you see in 1995 the stock 200 mercs and mariners came with the A17 computers and they had lean spots like i said witch was bad and burnt alot of motors so after they figured it out they went to the A32 box and reprogrammed the A17 and put those on alot of the 225 promax motors and if you get the A17 you need to make shore its the 200 A17 and not the one for the 225 because it will not perform good on the 200 the port timing is a little different Quote
fishn hard Posted February 1, 2011 Posted February 1, 2011 I found an ECU part # 824003 8, where as mine is 824003 1...would that part work or not? Does it say A8 Quote
Bass_Fanatic Posted February 1, 2011 Author Posted February 1, 2011 http://www.screamandfly.com/showthread.php?228544-Merc-efi-ecu Quote
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