2000 Mercury Bigfoot 50 HP 4 stroke-Low oil pressure

[nogimmies]

This thing is still driving me nuts---------------- 0T008360 ser #<br />I'm getting low oil pressure at idle and 1500-2000rpm.<br />At idle my tee'd in pressure gauge shows Zero<br />At full throttle 30-35 lbs<br />I removed the pump and inspected it.<br />It is on the bottom of the camshaft. Had to pull the head. It looks fine No scoring,scratches dings etc. The pumps tolerance specs measured within or better than the manual.<br />I'm wondering if there is something on the suction tube that could be defective or if there is some other o-ring between the powerhead and the adapter plate that could be giving me fits.<br /> When this motor warms up, as soon as you engage the throttle/ gearbox the alarm sounds.<br />I've also noticed that by pulling off the sensor lead to the sending unit the alarm still sounds until reset by shuting the engine off. upon restarting the alarm ceases with the wire off the oil pressure sensor. Which is normal.<br />This low pressure at idle has me stumped<br />Merc says(Factory) that at idle this thing should have 3-5 lbs to satisfy the sensor.<br />Any clues from you Merc Guru's??????

 

[nogimmies]

Re: 2000 Mercury Bigfoot 50 HP 4 stroke-Low oil pressure

I forgot to mention that Merc recommended going from 10-30 wt oil to 25-45.<br />I went One better and added2.5 qts 20-50 plus 1 pt of STP oil treatment the honey thick stuff figuring that if the pump pressure would increase.It did not.But i'm getting good lubrication. After running the engine I pulled off the valve cover and everything is coated well.<br />Still am looking for some answers or ideas<br />Mercury Marine Hdqtrs in Fond du Lac ,Wisc. so far is useless in helping with this problem.<br />This will be the last Merc I'll Buy.<br />I'll go to Yamaha or Susuki next time.

 

[HSEMJ]

Re: 2000 Mercury Bigfoot 50 HP 4 stroke-Low oil pressure

well it could be you oil pickup screen in the sump is partly pluged, or it's more likely the oil pressure relief valve is sticking open IMO. Which is located in the sump mounted on the bottom of the exhaust adaptor plate.<br /><br />ps: that engine block and head is yamaha made

 

[nogimmies]

Re: 2000 Mercury Bigfoot 50 HP 4 stroke-Low oil pressure

I found the problem and it was the pressure relief.<br />Pulled the powerhead and found relief sticking open.<br />Made repairs and now I get 40 lbs of oil pressure at idle.<br />Yaaaaahhhhhhhhoooooo<br />Thanks for the advice!!!!!!!!!!!