80HP merc oil pump going out?

[J_A_S]

I pulled my 80HP mercury (I think 1980’s) out to crank it for the first time this season and to much delight she fired right up! However, I have a suspicion that the oil is not getting mixed into the fuel properly because 1. Usually the gas/oil mix appears blue in the clear fuel filter right before the carbs and 2. Once it burned off what little gas/oil that was in the carbs it spit out no smoke. My question is; is there another way to confirm the oil mixing pump isn’t working? Also would it hurt to just go ahead and mix some oil into the gas tank and start running it like that? If so, what mixture?

 

[The Force power]

I pulled my 80HP mercury (I think 1980’s)

Any idea on how many versions of 80 HP Mercs. were made??!!

need Serial# to help you!

please read the the sticky notes on the top of this forum
https://forums.iboats.com/forum/engi...-your-question

Mercs. would be 50:1 mix-ratio and yes you can pour pre-mix straight in the fuel-tank & bypass the pump

 

[racerone]

Remove oil pump.--------Turn motor with rope on flywheel.-----See if shaft to oil pump is turning.------Gear ratio means that you have to turn flywheel about 20 turns to confirm if plastic gear on crank is intact.

 

[J_A_S]

Sorry, serial number is 08301950. I haven't been very successful in getting an exact year. What would be involved in bypassing the oil pump? Just run fuel hose from the connector in the front of the cowl straight o the carburetors?

 

[Faztbullet]

That's a 3 cylinder ...1987 and that a B not a 8

 

[J_A_S]

That's a 3 cylinder ...1987 and that a B not a 8

That would be why I’ve struggled finding a year...LOL. I’m going to take the pump off and check the gears when I get the chance. Any tips on bypassing the pump all together?

 

[The Force power]

That would be why I’ve struggled finding a year...LOL. I’m going to take the pump off and check the gears when I get the chance. Any tips on bypassing the pump all together?

Mostly along these instructions;

To disable the pump just undo the hose to it, unscrew the two screws holding it to the block, pull it out and pull the gear and the little skinny thrust washer around the gear shaft out. Put everything else back including the hose and leaving oil in your tank to keep the low oil warning from coming on. Without the gear turning the oil will not come out of the pump outlet hose.

 

[Faztbullet]

Those gears and pumps rarely fail on those models....

 

[Texasmark]

Mostly along these instructions;

To disable the pump just undo the hose to it, unscrew the two screws holding it to the block, pull it out and pull the gear and the little skinny thrust washer around the gear shaft out. Put everything else back including the hose and leaving oil in your tank to keep the low oil warning from coming on. Without the gear turning the oil will not come out of the pump outlet hose.

Right on. Did exactly that on my 2002 90 hp that had just passed 10 years old just because I slept better at night. No reason otherwise. I did take a magic marker and write instructions adjacent to the fuel filler to remember to pre-mix.

 

[mav6759]

I have a 2005 Mercury 90hp 2 stroke, and that is the very same reason I removed the oil pump altogether and mix mine 50:1. These motors are too dog on expensive to be playing around with. Mercury and Evinrude have always had issues with these oil pumps. Every since I had one go out and tore up my motor, I said never again..All the older guys that I know worned me about oil pumps. But I didn't listen, NO...because I was told that they had gotten better. But I never looked at all the issue these pumps had in the past. I have had 5 of my friends experienced the same problem and unless its a 4 stroke, I do not trust those oil pumps. I have been boating for the last 30 years and fishing all my life and involved in fishing clubs since I can remember, and every year we get 1 or 2 that ruin there motors because something went wrong with that oil pump..This is just my suggestion, I would disconnect that oil pump and mix my oil 50:1. That way you know it's right...just my thought....