84 merc 150 hp bogs down with beep

[jingy]

My 1984 Mercury outboard bogs down when trying to throttle up. History is as follows.
Running at top end the motor just shut down and lost power like it ran out of fuel and had Beep,Beep,Beep as was slowing down. I imediately checked my main oil tank to see if connector had come off (was OK) and the oil reservoir on top of the engine (was full and OK). I then Checked fuel connection and pumped up ball and it seemed fine and tried to restart engine. It started fine and idled ok so I tried to throttle up and it bogged down and had the BeepBeepBeep oil warning again so shut it down. I used trolling motor to get to launch and pulled cowl and found a lot of oil around the oil pump and below. The line form the oil pump to the tee fitting was cracked im sure iwas sucking air as well as less oil than I should. When touched it fell apart completely. Got home and I replaced this little line as well as the one from the reservoir on the engine. Put back in water and starts fine,no leaks,but when throttle up no power and a beep beep on some ocassions. There is some air in the little line before the Tee fitting and cant seem to bleed it out. I'm thinking I have a fuel problem and maybe a oil motion sensor problem. Am I on the right track? had no problems before this. Did something suck into the carb? Need Some Help Please!! It's a 150 v-6.

 

[j_martin]

Re: 84 merc 150 hp bogs down with beep

The beeping is the oil alert. There's nothing electronic to limit the engine, so the bog is definitely something mechanical. Given your description of the events and what you've found, I'd run a compression test on it, and expect to find major engine damage.

 

[jingy]

Re: 84 merc 150 hp bogs down with beep

Failed to mention that compression test done and all six cyliders around 120 +/- 2. Spark also looks good off plug wires. New plugs.

 

[j_martin]

Re: 84 merc 150 hp bogs down with beep

This is the second one like this in the last coupla weeks. I'm beginning to wonder if the oil pump has a seal that gets hurt if it's starved for a short period of time and allows air to get into the suction side. The pump should, by design, be able to cleanly suck against a 4 foot head (tank 4 feet below it) with ease.

The other guy wound up ripping the system off and going pre-mix. I don't know if he has any hair left.

If it's getting oil, the bog is unrelated to the oil alarm. It's another problem.

hope it helps
john

 

[jingy]

Re: 84 merc 150 hp bogs down with beep

Thanks J. for your help!!! I tried another spark test and low and behold number 1 had lost it's spark!! I moved it around a bit and regained it. Wire was barely in boot on coil side. Put in new wire and boot and spark is great. This could help with the bogging but I would think 5 cylinders would get er up? As far as the oil, the air stays in the short piece of tubing between the pump and the tee. I'm going to try and take linkage off pump and force feed the line to remove the air. I was told that at idle it should purge itself of the air but not in this case. Your seal idea makes sense! I'll see if I can find any air suction on the pump side external to the lines. If I can clear that up I'll try it on the water as with the muffs on I can't give it the load it needs. Do you think that the one cylinder not firing would cause so much bog? Thanks

 

[sschefer]

Re: 84 merc 150 hp bogs down with beep

Thanks J. for your help!!! I tried another spark test and low and behold number 1 had lost it's spark!! I moved it around a bit and regained it. Wire was barely in boot on coil side. Put in new wire and boot and spark is great. This could help with the bogging but I would think 5 cylinders would get er up? As far as the oil, the air stays in the short piece of tubing between the pump and the tee. I'm going to try and take linkage off pump and force feed the line to remove the air. I was told that at idle it should purge itself of the air but not in this case. Your seal idea makes sense! I'll see if I can find any air suction on the pump side external to the lines. If I can clear that up I'll try it on the water as with the muffs on I can't give it the load it needs. Do you think that the one cylinder not firing would cause so much bog? Thanks

On top of the oil pump is a banjo fitting with what looks like a bolt in the middle of it. Put some rags under the pump area and loosen that bolt. It will allow oil to flow from the tank and that little air bubble should come with it.

I recommend replacing the oil pump after it has been run dry, there is a pump seal that can be damaged. Pumps are cheap compared to what happens when you don't get enough oil.

 

[jingy]

Re: 84 merc 150 hp bogs down with beep

Thank you SS. The bolt you mention, is that the bleed screw? I tried that but with the resevoir on top it just fills the pump. The short oil line is below the pump and before the tee and the air won't rise. I presume the check valve in the tee won't allow it to let the gas come up the oil line. I'm not sure of what bolt you are referring to. My pump looks like the one at this site. http://continuouswave.com/whaler/reference/mercuryOilInjection.html . This is a good reference I came across. I'm learning from you guys and whatever I can find online. Thanks!!

 

[Faztbullet]

Re: 84 merc 150 hp bogs down with beep

Your answer in in the link you provided:

"Bleeding Air From Oil Injection Pump Outlet Hose
Any air bubbles in outlet hose in most cases will be purged out of the system during operation of the engine.

NOTE: If air bubbles persist, they can be purged out of the hose by removing link rod and rotating the pump air full clockwise while operating engine at 1,000 to 1,500-RPM. If necessary, gently pinch the fuel line between the remote fuel line connector and the oil injection pump Tee fitting. This will cause the fuel pump to provide a partial vacuum which will aid in removal of the air. Reinstall link rod.

The bleed screw(a) just bleeds air from pump so it will prime....