1971 chrysler 55 hp waterpump dilemma

[Don Grammer]

recently acquired a 55 hp chrysler,model # 554bc. put it in a barrel and cranked it over, it fired right up and sounded great, but no water circulation. pulled the leg to inspect waterpump, every thing looked brand new. the water intake tube was quite loose so I put a dab of silicone to seal it in. re-installed leg and put it back in barrel. fired it up and it pumped water perfectly. shut it down, drained barrel and noticed gear oil coming from water intake tube. pulled the leg again ,took out waterpump and seen it was full of gear oil, which had probably been sucked up through the drive shaft seal below the waterpump. to much suction and not venting,(my guess). decided to pull the water intake tube and clean off the silicone. when I pulled the intake tube I noticed what looked to be a factory drilled hole in casing. I pulled the drive shaft seal and noticed a drilled hole in the brass bushing below the shaft seal. I am assuming this is a gear case ventilation system and work in unison with the pump. before going further I would like some input.afraid I may have plugged the hole beneath intake tube and will get the same result after changing seal and waterpump.

 

[Frank Acampora]

Re: 1971 chrysler 55 hp waterpump dilemma

It is quite common to have lots of unburned oil in water when running in a barrel. The seal is not necessarily worn! Unless the water pump was completely full of oil, it may have sucked in some of the unburned stuff. You need to smell the oil: if it smells like gasoline, it is unburned lubricating oil. If it smells like sulphur--burned matchheads-- it is lower unit oil. Some water pumps have a fine vent hole to bleed air and assist in priming when the leg is under water. The hole in the top bushing is probably standard from the manufacturer and aids in lubricating the oilite bushing under certain applications.

Check the lower unit for water inside. If the seal is worn, the pump blows water down and the oil is displaced. If the seal is worn, it is relatively simple to replace.

 

[Don Grammer]

Re: 1971 chrysler 55 hp waterpump dilemma

Is definitely gear oil, the smell is quite distinct, and new gear oil to boot. I failed to mention I drained the gearcase after I purchased it and put new gear oil in. Am not familiar with Chrysler outboards ( very little knowledge of others ) but am mechanically inclined and enjoy working on engines. From past experience, any gearcase , ie. rearend should be ventilated. The gear oil was only in the waterpump and drain tube and you could see white creamy oil on top of the shaft seal so I assumed it sucked it up from the gear case. I much appreciate your input Frank. Would like to know if these drilled holes have anything to do with gearcase ventilation or if I have to look elsewhere for my dilemma ,eg. wrong waterpump.

 

[BuzzStPoint]

Re: 1971 chrysler 55 hp waterpump dilemma

This is a common issue some complain about. You'd be suprised the amount of oil that is in the barrel when running.

If in doubt, replace the seal.

But if you are taking the lower leg off do a pressure test. Drain your gear oil. Plug the vent cap, and connect an air hose to drain plug. Submerge in water and apply no more then 10 psi of air pressure. If you see bubbles, you know what seal is bad.

 

[Frank Acampora]

Re: 1971 chrysler 55 hp waterpump dilemma

Yep! rear eng oil has a distinctive odor due to the sulphur content. Once you smell it you will never mistake it for anything else.

There is NO venting of the lower unit. It must be sealed to prevent water intrusion. It is NOT like an auto rear end. It always runs cold because it is immersed in the best coolant in the world. There is virtually no expansion to worry about and a properly filled lower unit still has air above the oil. One plug is usually labeled "vent" But that is just for filling purposes. If you are not sure about the upper drive shaft seal, test the lower unit as Buzz said above.

 

[Don Grammer]

Re: 1971 chrysler 55 hp waterpump dilemma

I've already pulled the shaft seal so will be replacing it. I will do the pressure test when I replace the shaft seal. Still would like to know what the drilled hole in the recessed area where the water intake to waterpump goes is there for. Is it o.k to silicone intake tube in ?
As Frank explained , the drilled hole in the brass collar bushing beneath the shaft seal is probably for lube of shaft seal and stands to reason. Can't find any literature concerning the drilled hole beneath water intake tube.

 

[Don Grammer]

Re: 1971 chrysler 55 hp waterpump dilemma

Thanks Frank, did not know it was'nt ventilated and makes sense as it runs cool. Maybe a stupid question, but concerning the pressure test, would I not have to seal off the hole where the drive shaft goes in order to test? I was assuming the hole beneath intake tube was going into crankcase and worked in unison with waterpump to ventilate and maybe also keep shaft seal lubed via drilled hole in brass collar bushing. Therefore when I sealed the intake tube off it could no longer do the job. The reason I say this is becuase it had sucked up so much gear oil that the waterpump was completely filled with gear oil and when I drained the oil there was no moisture to speak of in the gearcase.It's as if I had plugged off any ventilation it should be getting and the ten vane imppeller had so much suction that it sucked gear oil through the shaft seal into the waterpump

 

[BuzzStPoint]

Re: 1971 chrysler 55 hp waterpump dilemma

As for pressure testing, you would put in all your new seals. You would be almost at the point of putting the LU back on.
Except your gear oil would be drained and empty. Close the vent and connect and seal the air hose to the drain.

Once you have the seal on under the water pump, and the drive shaft through it, the lower unit should be sealed from the top end.
Once the pressure test is done, it should hold air and no bubbles you are good to go. Reason we say no more then 10 PSI is because you can blow out your new seals.

As for to much suction on the 10 vane? Dont know, I actually can't remember what vane I put in my 55hp.