Help with oil injection part #

[FREDDYPD]

I have been following the smoking engine threads and have ordered part #21-8781051 which is a check valve for the oil injection system. According to the diagrams this valve connects to the remote 3 gallon oil tank. There is no valve at the tank location. It appears my valve is located on the starboard side of the motor and looks like it has hoses coming from 3 sides. 1 side goes to the remote tank, 1 side goes to a vent/drip hose and the other goes to the small oil tank on the engine.

Can someone tell me what part # I should order?

Thanks,
Freddypd

 

[j_martin]

Re: Help with oil injection part #

I have been following the smoking engine threads and have ordered part #21-8781051 which is a check valve for the oil injection system. According to the diagrams this valve connects to the remote 3 gallon oil tank. There is no valve at the tank location. It appears my valve is located on the starboard side of the motor and looks like it has hoses coming from 3 sides. 1 side goes to the remote tank, 1 side goes to a vent/drip hose and the other goes to the small oil tank on the engine.

Can someone tell me what part # I should order?

Thanks,
Freddypd

I don't know how that valve could fail and cause a smoking engine. Sometimes they leak and make a mess, but not often.

22-424252 TEE, OIL TUBING , 'bout 24 bucks.

It's actually a 2 lb suction breaker (check valve). The only time it comes into play is if the line to the tank in the boat becomes pinched off or plugged. It then lets air in through the drip tube so the oil pump can continue to draw oil out of the engine tank.


hope it helps
John

 

[FREDDYPD]

Re: Help with oil injection part #

Thanks John. The reason I am changing this part is because of these 2 threads:

http://forums.iboats.com/showthread.php?t=224359&highlight=smoke

http://forums.iboats.com/showthread.php?t=182406&highlight=smoke

I figured it couldn't hurt. Someone had mentioned that this valve may cause a backpressure in the system. Maybe I should hold off?

 

[FREDDYPD]

Re: Help with oil injection part #

OK. I did see that part #22-424252 on the parts diagram, but it still shows another check valve (part # 21-8781051) at the remote oil tank location. The hoses that go into the remote tank definitely don't have a check valve attached and it doesn't look like I could add a check valve there. Is that a problem?

This is the site that I have bought parts from and here is the diagram:

http://www.ishopmarine.com/ishop/js...cCatFilter=MM&eCatSupFldr=supplier-050-025-MM

 

[j_martin]

Re: Help with oil injection part #

OK. I did see that part #22-424252 on the parts diagram, but it still shows another check valve (part # 21-8781051) at the remote oil tank location. The hoses that go into the remote tank definitely don't have a check valve attached and it doesn't look like I could add a check valve there. Is that a problem?

This is the site that I have bought parts from and here is the diagram:

http://www.ishopmarine.com/ishop/js...cCatFilter=MM&eCatSupFldr=supplier-050-025-MM

That part looks like a barbed hose fitting, but it has a check valve and possibly pressure regulation built into it. It screws into the motor, and provides about 2 lbs pressure to the remote oil tank to push the oil up to the engine tank. It should slowly bleed back after shutoff so that there is no pressure after a couple of minutes. The test is to shut down, wait a couple of minutes, then crack the cap on the remote oil tank. There shouldn't be any pressure there. If there is, the crankcase check valve is bad. If it doesn't relieve, it'll slowly fill the fuel lines with oil just before the carbs, causing a smokey, hard start. After that it'll run fine.

If the line between the mixing T and the first carb is clear tygon, you could visually verify the oil push described above.

The other valve you mentioned does not relieve that pressure at all, but relieves a vacuum if it occurrs, as it would if the remote tank lines got pinched.

Have you looked up the oil system in your maintenance manual and checked the alignment of the throttle linkage to it?

hope it helps
John

 

[hkeiner]

Re: Help with oil injection part #

I had similar problems with excessive smoke on my motor and did some extensive research on the oil injection system to determine which failed check valves might cause this and which failed valves might not cause this. In short, I determined that check valve (#5) could not cause excessive smoke as it's sole purpose is to prevent vacuum in the oil line. If it were to be stuck open, it would cause oil to drain into the motor area. If it were to be stuck closed, it would fail to prevent a vacuum and cause insufficient oil to reach the motor. Neither of these scenarios would cause excessive smoke, however. The other two check valves, on the other hand, can cause excessive smoke so I replaced them and it solved my problem.​

The below link provides a pretty good guide on how the oil injection system works. Check valve #5 is labeled as such on the diagram.​

Valve #5) If oil flow to reservoir is obstructed and injection pump continues to pump oil, the 2-PSI valve will open to allow air to enter reservoir to prevent a vacuum. ​

Valve #6) This valve prevents gasoline from being forced into the oil lines. It is an in-line valve located on the hose going between the oil pump and the fuel pump.​

Not numbered) Crankcase pressure with one way check valve. This valve is screwed into the crankcase on the starboard side of the motor near the starter. A hose runs from this valve to the remote oil tank.​

http://continuouswave.com/whaler/reference/mercuryOilInjection.html

 

[FREDDYPD]

Re: Help with oil injection part #

John,

My Oil throttle linkage was not aligned correctly and I did change that. I will do the test you suggested about checking pressure in the oil tank. Thanks.

Hal,

Is part #21-8781051 the one that is not numbered in your diagram? I have it and was not sure where it goes. According to the ishopmarine parts diagram it looked like it gets installed at the remote oil tank location which is not possible on my boat. According to your replies it looks like it may get screwed to the motor near the starter. Is that correct?

 

[hkeiner]

Re: Help with oil injection part #

Is part #21-8781051 the one that is not numbered in your diagram? I have it and was not sure where it goes. According to the ishopmarine parts diagram it looked like it gets installed at the remote oil tank location which is not possible on my boat. According to your replies it looks like it may get screwed to the motor near the starter. Is that correct?

Yes, part #21-8781051 is the unnumbered CRANKCASE PRESSURE WITH ONE WAY CHECK VALVE. It screws into the crankcase near the bottom of the starter. If you follow the hoses from the remote tank to the motor, one connects directly to the crankcase check valve.

Please also note that the valve you recently purchased will be slightly smaller in size than the original valve. According to my local boat shop, Mercury redesigned the valve to make it better. The thread size is the same, but the overall size of the valve is smaller.

 

[FREDDYPD]

Re: Help with oil injection part #

Hal,

Thanks so much! I guess I was focused on the wrong thing and could not find the obvious. I changed the part, adjusted the oil linkage, and did a full decarb with seafoam. Wish me luck.