9.9 JOHNSON 1978

[hank38]

I'M TRYING TO REPLACE MY WATER PUMP BY THE SHOP MANUAL INSTRUCTIONS. IT SAYS TO REMOVE THE LOWER UNIT 6 UPPER BOLTS (I HAVE A LONG SHAFT WITH 5" EXTENSION) AND THE LOWER UNIT SHOULD DROP DOWN APPROX 1/2 INCH TO EXPOSE A SHAFT CONNECTED BY A FLAT COUPLING WITH 2 SCREWS AND I'M TO LOOSEN THE TOP SCREW AND LOWER THE UNIT ALL THE WAY DOWN AND OFF. PROBLEM IS THE UNIT ONLY DROPS DOWN ABOUT 1/8 INCH. I CAN ACCESS THE COUPLING WITH A SCREW DRIVER AND I CAN MOVE THE COUPLING AND RODS UP AND DOWN FREELY, WHICH MEANS ITS NOT HANGING ME UP HOWEVER, SOMETHING ELSE IS AS THE LOWER UNIT WON'T GO ANY FARTHER DOWN EVEN WITH A RUBBER MALLET PERSUADER. WHAT COULD BE HANGING ME UP AND HOW DO I REMOVE MY LOWER UNIT THE REST OF THE WAY? ARE THERE ANY SPECIAL TOOLS INVOLVED?

 

[Joe Reeves]

Re: 9.9 JOHNSON 1978

Put the engine in reverse gear and spin the prop slightly to make sure the shifter dog engages the gear lobes.

That will allow the lower unit to drop to the level you need.

 

[Xcusme]

Re: 9.9 JOHNSON 1978

Hank, Remove that coupler bolt, not just loosen it. It has to come out to release the shift rod.....if you drop it into the case, not to worry, you can retrieve it when you drop the lower unit. It can't go anywhere.

 

[hank38]

Re: 9.9 JOHNSON 1978

Put the engine in reverse gear and spin the prop slightly to make sure the shifter dog engages the gear lobes.

That will allow the lower unit to drop to the level you need.

 

[hank38]

Re: 9.9 JOHNSON 1978

Joe/Guys,
I played with the motor last night for an hour but still couldn't get the lower unit to drop down. I did manage to remove the upper screw on the shifter rod coupling and seperate the upper/lower rods. I put the motor in reverse and turned the prop but the lower unit wouldn't drop down. However, I'm not sure I'm clear on the portion of your reply about the shifter dog and gear lobes? Are these located within the lower unit or up by the motor head? I didn't see a clear picture in the repair manual showing the extreme upper end of the shaft that goes up from the lower unit to the engine so I don't know how they engage/disengage. If I cannot get the lower unit to drop, can I disassemble the upper unit to get it off? Thanks for your first replay and all the help!

 

[Xcusme]

Re: 9.9 JOHNSON 1978

Hank,
The part about rotating the prop was to help you get the gear case in reverse gear so there's more travel for the lower unit to drop a bit more and remove the shift rod bolt. You're past that point since you have the bolt out. The only thing holding the lower unit on the power head is the drive shaft. The top of the drive shaft is splined. It mates with the crank shaft and 'should' slip down and out of the crank shaft. You have a classic example of the drive shaft either being rusted into the crank shaft or metal displacement of the splines, preventing the drive shaft to drop. Doing a search of the forum for 'stuck drive shaft' will point you to possible fixes. The usual solution involves inverting the motor and spraying PB Blaster penetrating oil down the drive shaft. Soaking the crankshaft/driveshaft junction and gentle persuasion usually separates the two. To help prevent the same situation in the future, be sure to apply grease to the drive shaft splines when you reinstall the lower unit.

 

[hank38]

Re: 9.9 JOHNSON 1978

Hank,
The part about rotating the prop was to help you get the gear case in reverse gear so there's more travel for the lower unit to drop a bit more and remove the shift rod bolt. You're past that point since you have the bolt out. The only thing holding the lower unit on the power head is the drive shaft. The top of the drive shaft is splined. It mates with the crank shaft and 'should' slip down and out of the crank shaft. You have a classic example of the drive shaft either being rusted into the crank shaft or metal displacement of the splines, preventing the drive shaft to drop. Doing a search of the forum for 'stuck drive shaft' will point you to possible fixes. The usual solution involves inverting the motor and spraying PB Blaster penetrating oil down the drive shaft. Soaking the crankshaft/driveshaft junction and gentle persuasion usually separates the two. To help prevent the same situation in the future, be sure to apply grease to the drive shaft splines when you reinstall the lower unit.

 

[hank38]

Re: 9.9 JOHNSON 1978

OK. Here's how it played out. I flipped the engine upside down and soaked the shaft with WD-40 for a few days. I still could not free the drive shaft from the engine. I next installed 6-bolts, 2 inch long which were threaded the entire lingth (no shoulder). I also installed a nut and washer on each bolt prior to threading the bolt into the upper housing as there was just enough space btwn the flanges for the nuts/washers. With the bolts threaded into the exhaust housing's threaded holes, I then used the nuts to "jack" the lower unit with 5 inch extension up to widen the gap and eventually seperated the housings. What actually happened was the drive shaft pulled up and out the lower unit, pulling the impeller lock pin up through (damaging it in the process) the seal on the upper end of the water pump. In other words the drive shaft was still stuck in the engine. At this point I snapped a pair of vice grips tightly on a non seal mating portion of the drive shaft and tapped (beat) on the vice grips until the drive shaft seperated from the engine. I then installed a new pump kit, dressed the marred area of the shaft, topped off the gear box oil, reassembled everything and lake tested the engine/boat........they seem fine.
FYI, I don't think much of the WD-40 was getting down to the engine/drive shaft spline area due to a white round plastic piece that the drive shaft goes through, I think it blocked most of it. Also, the old impeller was completely intact however, the blades were permanently rolled over pretty far and the metal hub was completely detached from the rubber blades......it was time for a change. Joe and Xcuse Me, thanks for your help it helped me a lot.........Hank.

 

[OptsyEagle]

Re: 9.9 JOHNSON 1978

I think that is why they recommend that you grease these drive shaft splines whenever you are putting them back together. Without it they tend to bond together.

 

[mikesea]

Re: 9.9 JOHNSON 1978

Think I can help.Those engines with the extension have a small area where the water tube goes through,what happens is between the copper water tube, alum.casing and a rubber bushing,the water tube becomes cemented ,not allowing it to come apart. I have cut the water tube and later used a pipe coupling and sweated it back together.The driveshaft problem is possible,but I have seen these extensions cause this problem many times. Especially down here in S.Fl with the salt.The exrended engines are often on sailboats,which owners feel their engines get little use so what is the need to replace the impeller so often. This is why.I always told customers,the kicker is the engine you want to be in the best condition.Oh,I would also remove the bolts that hold the extension to the engine(top bolts)split it there and get a hacksaw blade or sawzall and cut the water tube there. That would be on top of the area that it gets stuck.Cutting the water tube first means you only need to put a coupling to join it,cutting the drive shaft first ,could be an unessary ,very expensive mistake. Let us know how it works out.