Logo
FULL SITE MENU

2012 Mercury 90 hp 4 stroke efi need help.

K

kfsrmn

New member
Bought this thing used and looking like a mistake. It had 266 hours and looks like new. I installed a new Quicksilver impeller kit, new filters, and new oil. Sprayed the air filter with K&N. I took it out and the low pressure pump was not keeping up. It had been replaced along with the float 6 months before I bought it. I replaced the pump and installed a Boat View. Got it running but it was shutting down on high temp. It has a good stream. I replaced the thermostat and the old one was in backwards so someone was in there. I had to double check that. Still over temp so I changed the sensor. It ran good for about an hour and a half this morning except I was getting a beep and hesitation about every 5-8 minutes. No fault showing. Then I got a string of beeps, I think 6 and a sensor problem fault on the boat view. It did not shut the engine down but I headed back to the launch. Did it a 2nd time on the way back. I have no idea where to look next. It did not say which sensor. Trying to get a boat into a shop right now is a problem. They are backed up.
 
Thinking this over I am wondering if the hesitation is being caused by the high pressure pump? Should have replaced both pumps while I had it open.
 
I found out the Vessel View does have codes or tells you the part. Watched YouTube. It says the throttle body sensor TBI. I will have to replace the TBI and hopefully that cures the problem. At least it is an easy one to replace.
 
Replaced the throttle position sensor. Took it out this morning. Started fine and idled out of the no wake. Kicked it up to 4000 rpm and it ran smooth for about 5 minutes when I got a long beep and it basically ran out of gas. Turned it off and back on. Single beep and the lift pump was running. Waited for the pump to stop and started it. It took off again then quit. Long single beep. The lift pump is either not keeping up or possibly the float is not telling it to fill. The float is 7 months old and it is filling when I turn it on. I did not get a fault on my vessel view. I am out of ideas.
 
Solved the fuel problem by replacing the fuel lines. The engine still shuts off for a second and comes back on like someone is turning the key off and back on quickly. After 45 minutes the throttle position sensor alarmed again even with the new sensor. Does not shut down but will alarm again in 5-10 minutes. This is leading back to the ECM. I need someone to test it again. Nothing showed up last time it was checked in the shop. The ECM is just under $1000 so I am hoping that is not the problem.
This has had quite a few views and no suggestions. Looks like I am wasting my time here.
 
I chased this ghost 2 yrs ago at shop , with a 2014 , 60 hp. Motor ran fine on muffs. Put in water, run wide open for 200 yards. 6 beeps, and ecm would go into guardian mode, making motor half power. As long as I ran half power on plane it ran fine. OK ��. 6 beeps is iac- iat,map or tps sensors. Termostat was backwards? Spring part of termostat goes in first. You need to drop lower unit, pull termostat, take water hose and stick in where thermostat goes , turn on water a watch what comes out water tube ( bit and pieces of old impeller, have someone hold a empty Gatorade bottle at water tube at lower unit) and see what comes out
What can happen is sand was sucked up or impeller pieces create a blockage. Back to motor I was chasing with 6 beep alarm (code don't remember) iac-iat, map or tps sensor fault that ecm was telling my MEDS diagnostic program was problem. Wasn't the problem at all. Termostat was full of sand. So what had happened is motor over heated ecm , and cooked it.
Luckily ecm would still throw it in guardian mode and not blow up motor. Fix was a new ecm about $800 , that was the newer single plug ecm up front. I'm not saying that it's your issue, just telling u what I've seen.
 
Closely resembles my current issues but no alarms. Mechanic had a overheating code, replaced impeller, code gone but same problem.
Fuel pressure, injectors tested and cleaned, plugs, fuel filters, fresh fuel, compression test cold and hot
They “think” it’s a faulty ECM.
Currently waiting for mechanic to call mercury marine technician for advise.
2013 mercury 90hp outboard EFI 4 stroke serial 1B986113
 
Last edited:
The water flow is fine. The new thermostat came installed in a new housing. Old one was definitely in backwards. Tech was Huh? ALso installed new temperature sensor. Vessel View says I am running in the correct temperature range 124-130 f. There is no alarm or fault on the bumps. It shuts off for a second and keeps running. Start up beep sounds each time. Just like turning the key off and back on quickly. I reset the ECM and it ran 17 minutes and bumped then 4 minutes and again 4 minutes. I really had my hopes up when it went 15 minutes. Headed in. Consensus is the ECM. New $900. Used $450 and $270. Don't really trust them and how many hours? Got a quote from G7 Electronics $225 rebuild. Reviews are all over the place. Other quotes $625 and $700. For the difference on the high quotes I would just as soon buy a new one. Any one know a rebuilder? Mine is a double plug. Old part number 89772720T. New number 8M0083209. My engine has 270 hours. New impeller kit, lube, oil, filters and sprayed the air cleaner with K&N. Runs great when it runs.
The 6 beeps on the throttle position sensor fault does not put it in guardian mode. The Vessel View shows the fault. Overheat fault did put it in Guardian.
My son is an auto tech and teaches diagnostics. Unfortunately he lives 600 miles away. He has been thinking a failing part on the ECM. He does not have the test equipment to diagnose boat engines or I would send it to him.
 
Ecm , is sounding the 6 beep , it's brain is scrambling, doesn't know. Got 2 sea doo 4 Tec superchargered , at shop that ecm brp stuff, thinks it doesn't have oil pressure. And 1 thinks it turned over.
 
ECM was reprogramed. The TPI problem went away. The intermittent pauses did not but I may have found the problem. Too long an idle time. It paused so I took it up to 4800 RPM for 20 minutes with no bumps. Took it back down to 3800 RPM for 25 minutes with no bumps. Ran it for an hour total and no TPI fault. I am going to put new plugs in just in case. May also be related to fuel in the tank when I bought it. I have been using 76 lately. Going for no ethanol instead of additive.
 
Back
Top