Nipples

[bwhalerman]

Re: 1988 Mercury 70hp

Best way is to remove the carbs and tear apart and install a kit. Use plenty of spray carb cleaner. <br /><br />I personally removed my oil injection and capped off the line from the oil tank at the fuel pump and removed the oil pump gear and oil tank. As old as the 1988 model is I dont worry about it.

I have the same motor. It powers a 1989 17' Boston Whaler Montauk. Bought it in December 2014. Ran it all last summer no problem. Properly stored it over the winter now it has been bogging down. Since it's an older motor and I don't know what has been done to it I dug in and did a fair amount of PM. All new gas lines, rebuilt the fuel pump, new primer bulb, new male and female fuel connectors, new water separation filter. This past week I took it out for a shake down cruise and it ran ok but after a short period of time it would bog down and act like stalling. I pumped the primer bulb and she took off. I know I'm good all the way up to the carburetors. At low idle it sputters and wants to quit. Once the horn sounded. My guess is running too lean so I'm digging into the carbs. By the way it is good advice to do all the cheap stuff first i.e. gas line tests, enrichment test...oh yeah I also installed new plug wires and plugs. Tested coils...good to go, compression is 108-110 in all three cylinders, spark is strong. Buy a couple basic tools like spark tester and compression gauge.

Now I have a question and hope someone has the answer. The oil injection system was removed before I got the boat. I mix each fill-up with quicksilver oil and additive. Always fresh gas on board. If you have the cowling off the engine and look directly under the flywheel there is a nipple. Directly below it at the lowest part of the motor is another nipple. Both are not connected to anything but they are spitting out liquid. Not sure what these connections are for can't find them in the manual.

 

[GA_Boater]

bwhalerman You almost got the record for posting in an old thread from 2003, but earlier someone beat you by posting in one from 2002. Please read the Help Tip on top of the page about posting in old threads. The best way to get advice is by starting a new, fresh thread

This is your new thread.

 

[pckeen]

Not sure about the nipples, but your first step will be to rebuild the carbs.

 

[bwhalerman]

Carbs are off the motor and on the work bench last night. Floats are set based upon motor spec. now had to slightly adjust one. the guts look fairly clean but will put them in some cleaner, clean the jets. Needle valves appear to be in good shape. When my kit arrives I'll get them back together and head to the river for adjustment and testing.

 

[bwhalerman]

No Title

I have attached photos of the connection I have asked about. I'm trying to find out if these two nipples should be connected and what function they serve. Any information would be greatly appreciated. The motor is 1988, Mercury, 70hp. The automatic oil injection system was removed.

 

[flyingscott]

They look like they are connected correctly that line is to lube the top bearing.

 

[bwhalerman]

They look like they are connected correctly that line is to lube the top bearing.

Thank you for the information. I have spent hours trying to find some information on this. When I purchased this boat & motor they were not connected. So, I ran the tubing between the two. What material is lubricating the top bearing and where is it coming from?

 

[flyingscott]

Excess oil that collects on the bottom of the crankcase gets pumped up through that line.

 

[bwhalerman]

Excess oil that collects on the bottom of the crankcase gets pumped up through that line.

Thank you for the additional clarification. In the fuel circulation process does some of the oil mixed in my gas cans separate and fall to the bottom of the crankcase and that oil is recycled? I'm assuming that since the oil injection system was removed there would be no need for these two connections. Would you concur with that thought? If both fittings are no longer necessary are you aware of any parts that could be used to cap both the bottom outlet and upper intake? If they remain connected and no longer server a functional use would this additional low level of oil transfer effect engine performance? I may have noted before that when the line is disconnected at both ends a very minor spray comes from the bottom outlet. I would assume the upper intake connection would suck air and effect performance.

The bottom line I'm looking for is whether or not these two connections are necessary given the removal of oil injection and if not is there some product I can use to cap them.

Thank you very much for your help. It is greatly appreciated.

 

[GA_Boater]

Oil injection or pre-mix have nothing to with the purpose of the hose. And oil wouldn't be separating out of pre-mixed fuel.

During normal operation some oil collects at the bottom of the crankcase and the hose directs it to the upper bearing for lubrication. You need the hose and fittings for upper bearing survival.

 

[bwhalerman]

Oil injection or pre-mix have nothing to with the purpose of the hose. And oil wouldn't be separating out of pre-mixed fuel.

During normal operation some oil collects at the bottom of the crankcase and the hose directs it to the upper bearing for lubrication. You need the hose and fittings for upper bearing survival.

Thank you very much for rounding out the information. I even checked with Mercury on-line and they were not very helpful.