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Mercury 60 HP EFI 4 Cycle Bigfoot Problems

M

Mechanically Declined

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I've read old posts so thought I should comment on what I discovered today. Have a 2007 motor and have run premium fuel since new. Started idling and running rough and finally would not stay running. After replacing everything to the motor including the pickup tube in my tank (pontoon boat) that had become brittle and finally broke apart, I still had a problem idling with a loss of power. Would not stay running so started searching the threads on all of the sites. Changed the low pressure fuel pump and was pretty ticked that they couldn't design the latch for the motor cover so I would not have to remove it in order to pull the pump. Pump was not the problem. Then read about the "VST" (didn't know what it was until yesterday). Thought that might be the problem so I removed it, opened it up and it was clean as could be. My son noticed it looked dark in the inlet so I blew compressed air backwards and had little black particles blowing out. It was noticeably easier to blow air in so put it back together and installed. Was trying to figure out how to clear the fuel line just in case so decided to keep the electric high pressure fuel pump harness disconnected so it wouldn't run dry while letting the low pressure pump clear the line. Decided to give the primer squeeze bulb some pumps prior to anything else and got a line full of black particles (practically clogged the line) out of the hose and on the rag. It appears that the inside of the fuel line is disintegrating. I ran fuel through until clear and then hooked it up. Boat ran and was fine on a test run other than a little rough. Not sure if others are finding that the lines are not able to hold up but I will replace it with a hose that is resistant to ethanol fuels. I've had the same particles but not as much in my fuel filter so will look at that line as well. Was pleased that the stuff didn't enter the VST and create larger issues with the fuel injectors. This repair is not recommended unless you're a good backyard mechanic. Took some pics if someone wants to take a look (will try to attach if requested). Many thanks to the other posters that got my boat around the cove today.
 
merc sells some gas additive cleaner....dont remember the brand but it a yellow fluid....i would run a tank of gas thru it with a triple dose of that....i run a 2011 60 bigfoot and you will be lucky if you are completely out of the woods on it.....the injectors were contaminated....i contaminated the motor when it was brand new...please post the pics..i am curious... do you have a canister type water filter on it?....any efi engine is more critical than a carb engine..
 
Docksidemarineservices said:
It's called "Power Tune".
Click to expand...

Thank you. To both comments: Yes on canister and replaced when I thought it might be the problem. Gasket was rotted and thought it might have been letting air in. The flexible tube in my tank happened to break just following it was (is again) polyethylene tubing with a filter on the end of the tube. I purchased just a week ago from Mercury both the cleaner and stabilizer. Might actually have accelerated my problem of deteriorating lines. Ran it again this a.m. and still good other than not a smooth idle speed (idle only on the river so that's still a problem).. Great when I'm higher RPM's so not starved for fuel. I changed my plugs last week as well, eliminating the items that I can do myself. First time I pulled the cover, I put it back on without even trying to figure out what all of those wires and gadgets go to but it's getting better the more I read the problems and solutions in these threads. Photos are also great. I'll try to attach the photo with the inside of my fuel line on the rag. Will try that again later, gives me an error so might not like the file size or something. Rag covered with the black pieces and "goo" that was the wall of my line. Need to find out where to pick up the proper fuel lines for this caustic ethanol that is the only gas in town. Thanks again.
 
That and Quickstor is the other product I picked up. Looks like part of a fuel care system numbered 1, 2, 3. Next step for me is to find replacement lines. I picked up a marine grade line at NAPA when I changed out my canister assembly off of the tank but will now have to check to see if it is good for ethanol fuels. My big worry right now is the line from the fuel filter to the VST. It was pushing out the black stuff and should have never been allowed to be placed on a motor considering that we have no choice in the fuels we have available (all with ethanol here). Likely millions in repairs and scrapped motorized equipment. I remember fuel lines never giving any problems until they dry rotted and cracked. The fuel literally was stopped at the VST float and needle so the inside of it and my high pressure pump were nice and clean. Hoping that my injectors stayed clean as well. Will try again with posting a photo tonight. Thank you.
 
IMG_1352.jpg
If photo attached: This is what came out of the short run of fuel line from the filter to the VST. Came out like black Icee mix. Think I'll replace some fuel line prior to cranking it up again and will get the Mercury additive that looks like it does the most to counteract the ethanol.
 
I have a 60 HP bigfoot. It runs 4.7 amps in both legs and the dashboard says 11 amps is this right or too low
Thanks for any help
V Eric
 
Don't forget that there is a Schrader valve on the VST to confirm High Pressure Pump pressures. It is your friend when trying to diagnose VST issues. Connect it when every thing is fine and write down your pressures. The Shop Manual has a lot of information on the VST and the High Pressure Fuel flow in general.
 
Don't forget that there is a Schrader valve on the VST to confirm High Pressure Pump pressures. It is your friend when trying to diagnose VST issues. You can check the VST pressure at both Idle and under throttle to see if you need to go back into the VST again. The Shop Manual has a lot of information on the VST and the High Pressure Fuel flow in general. Also, There are micro filters on both the high pressure fuel pump and pressure regulator in the VST that get clogged. Make sure of the integrity of the fuel lines around the VST to insure NO air leakage. It only takes a small amount to make you chase your tail. Dungar Marine has a great write-up on VST's and cleaning them. Here's the link.
https://www.youtube.com/watch?v=eVdJ4BvRVYQ
 
My 60 hp Merc has been running fine, starts up great....when you push throttle forward, runs up great....but as soon as you back on on throttle, it cuts off....restarts great....but again run it up fine...then back off and it quits...fuel line, primer bulb/pressure great. Thanks.
 
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