Lower Unit Question

[73merchead]

Is it possible to replace the gear shaft seal, and the prop seal without the "special tools" on a 1973 Mercury 650 65hp 3 cyl. engine? If so any advice would be greatly appreciated. Also, could the lack of gaskets around the drain plug, flush, and vent plug, cause water in the gearcase. There're no gaskets in either plug?

 

[ricksrster]

Re: Lower Unit Question

"Special tools" are worth the investment if you plan on doing your own maintenance and service. The tools pay for themselves by reducing labor charges at the shop. The jobs go much easier and you will have less damage.
The drain and vent plug gaskets are very necessary to keeping water out of the lower unit. They should be changed every time you change the gear lube. They are very inexpensive at the local marine dealer. I buy a bunch at a time just to have them around.

 

[73merchead]

Re: Lower Unit Question

so changing these seals can be done without the tools and with a little elbow grease. My mech. estimated $350 to $400 for him to change the seals! I'm not a rich man so I have to do the work myself.

Any advice on which tools I would have to have and where to get them from.
1973 mercury 650 65hp 3cyl. serial# 366....!

Thanks for your help! Any is appeciated

 

[73merchead]

Re: Lower Unit Question

bump. please help

 

[Chris1956]

Re: Lower Unit Question

Changing the drive shaft seals does not require any special tools or knowledge. There is a seal in the water pump base, that seals to the driveshaft. it is the same price to buy a new water pump base, as it is to buy the seal itself, your choice. The other seal on the waterpump base is an o-ring.

The propshaft seal is a real problem to replace, even with the special tools. The special tools, BTW, are a spanner to remove the donut-shaped retainer, and a puller to pull the bearing carrier. You can adapt a harmonic-balancer puller to pull the bearing carrier, and likely rig up some "son of an erector set" tool to remove the retainer.

BTW - I would replace the gaskets and seals of the waterpump base first. That has shown to be the source of most of the gearcase leaks. Don't forget the fill and vent gaskets as well.

 

[73merchead]

Re: Lower Unit Question

After doing some searching and a little questioning from the previous owner, he supposedly changed the oil in the gearcase. He also said he changed the impeller. The motor hasn't seen the lake, I ran it with muffs. I know I should do a vacuum test to find the problem but I don't have the resources, nor the money to have a mechanic look at it. Should I start with the water pump seal, seeing as the lower unit hasn't seen any water?

thanks

 

[Chris1956]

Re: Lower Unit Question

I would do exactly that. Replace the two seals in the waterpump base and the gaskets and see what happens. Change the gear oil and use gaskets on the fill and vent plugs.

 

[73merchead]

Re: Lower Unit Question

well pulled the gearcase off, got to the waterpump, and first issue is the on of the fins on the impellar was broke about an inch from the end. Got to the first gasket, and seen oil between the pump and the gasket. On to the next gasket where I found the same and a craked pump base.

Also, while I'm there I noticed that the gear shaft move up and down probably a half inch or so! Is this normal? Don't know whether it's moving due to the fact that it's not attached to the motor or don't know!

Another thing don't buy anything from Wingfoot Outboards on EBAY. The guys a liar and a crook. Don't mean to bash anyone just trying to save someone some headaches. As I've got a massive migrane from this gentleman. Buyers beware!

Thanks Chris for your time to help me with this issue.

 

[emckelvy]

Re: Lower Unit Question

Very likely you've found your water intrusion problem. I wouldn't touch the propshaft seals unless you find oil seeping from them when you have motor tilted down.

Regarding the driveshaft play, you'll probably note that at the end of the driveshaft is a spring-loaded pin. This lower unit uses a tapered bearing on the driveshaft, and the pin provides pre-load (with the lower unit installed) to force the bearing against its tapered race.

A bit of free play is normal with the lower unit removed, and with the water pump base pulled the shaft is going to slop around at an alarming rate! All normal.

You'll probably guess that this pin is very important and if it's rusted such that it doesn't move freely when pushed, it's not going to provide any preload; this can ruin the gears. If your pin is stuck, soak it with PB Blaster and give it a few taps with a small ball-peen hammer or other suitable implement to loosen it up. Be careful with application of heat to help free it up, if you get the end too hot it'll remove the temper of the spring.

Apply a little spline grease (or waterproof marine grease) on the pin and the driveshaft splines when you reinstall the lower unit (but don't load up the top of the driveshaft with grease).

Good thing you pulled it down and found that busted impeller, normally only one overheat will melt down a 650 Triple block and ruin your whole day! Not a bad idea to renew the impeller every year on these.

HTH & G'luck with the repairs...........ed

 

[73merchead]

Re: Lower Unit Question

Should I be worried to see new headgaskets. I did see some oil on the ground the first time I ran it, from the prop! URRRGGHH! Well, I'll replace the water pump, hopefully on Wednesday. Fill the case up with oil and see what I've got. Hopefully my water issue will be resolved, and the oil seepage was just build up as the engine has sat for who knows how long.

The boat has been a headache from day one. It's a 1973 Glassmaster 16ft. It had rotted floors, and a 1973 Evinrude that supposedly needed a power pack. A whole new ignition system(stator, powerpack, rectifier, coils, spark plugs, and battery,) and still no spark. I went ahead and replaced the floor, new carpet, seats, and lights. Found this Merc on ebay and paid $1300.00 for it. Now $300.00 later she still sits in the garage. I'm begginning to get really frustrated and my wife is running out of patience everytime I ask for her blessing on another part. Good looking motor though!

 

[Chris1956]

Re: Lower Unit Question

Tht pump base could have been cracked when the prevoius owner installed it. You need to make sure you put the correct Oring on the base and work it into position, by hand, don't force it wit the nuts. Corrosion also makes this step hard. When tightening the water pump nuts, also be careful not to crack the upper or lower housing.

 

[73merchead]

Re: Lower Unit Question

I'm purchasing the entire water pump kit! I was told that It contained all of the gaskets o-rings, plate, and impeller. It costs around $80.00, does this sound right? After removing the base I was looking for shims, but couldn't find any. I see what looks to be tiny washers but they won't come off! Do all motors have some sort of shim or is it based on a motor to motor basis?

Thanks for all of your help guys you've saved me a lot of headaches!

 

[Chris1956]

Re: Lower Unit Question

Merc, That water pump kit sounds like the correct price. Usually the upper kit and the lower kit are about $40 each.

You may or may not have shims under the waterpump base. There are different designs of driveshaft bearings, some use shims some don't.

You will have extra parts (gaskets and orings) left over. Make sure you use the correct O-ring around the water pump base. Use the largest that will install by hand and grease it.

BTW - The 3/4" o-rings that may be left over can be used if the cylinders of your power trim/tilt system start leaking around the trim cylinder rods. These normally are used on the top of older non stainless steel driveshafts and Alpha-1 Gen I driveshafts as well.

 

[73merchead]

Re: Lower Unit Question

Well replaced the water pump, and still have water in the oil. It was coffee with cream colour. The clymer manual sucks as far as explaining things a novice can understand. Luckily I have a spare set of gaskets.

Anybody have any advice as to how to install. Do I use gaskant sealant on every gasket? I had two extra o-rings, A BIG ONE AND A SMALL ONE, and an extra gasket. Should I use two gaskets on the base?

Any and all advice is GREATLY APPRECIATED!

 

[Chris1956]

Re: Lower Unit Question

You do not need to use any gasket sealant. It is normal to have orings and gaskets left over. I would expect you to have at least 3-4 of each left.

Did you replace the waterpump base? That is most important since it is where the driveshaft seal is located. Isthe driveshaft smooth in the area where the seal rides? If not, can you smooth it a bit with some emeory cloth? Did you use te correct large Oring on the base? I put a thin film of marine grease on everything. Hope you have some luck.

 

[73merchead]

Re: Lower Unit Question

I did replace the pump base, and the o-ring I used was the smaller of the two big ones. The biggest one seemed to be a little too big, just didn't snug up the way I'd like to see it! I'm sooooooo frustrated with this boat bout ready to run it till it blows up.

 

[Chris1956]

Re: Lower Unit Question

OK, Let me butt in one more time. Use the biggest Oring on the waterpump base, that will go in with hand pressure. Don't forget the pump base gasket. Make sure the driveshaft seal is not torn and the driveshaft is smooth (no rust) where it emerges from the gearcase. On top of the pump base another gasket, the SS plate and another gasket. Then install the drive shaft key and the impeller. Now lube the SS liner of the pump cover and install the waterpump cover, turning the driveshaft CW while you push down on the cover.

 

[73merchead]

Re: Lower Unit Question

Well, thought I had this problem resolved but she has bitten me again. Took her to the lake on fathers day, and she ran like a champ! Gott'r home drained the gear oil, and found a little water in it? Got to looking at the prop and noticed a significant amout of gear oil around it. When I refilled the gearcase I hear air coming from the prop shaft area. Sounded like a flat tire. Would everyone say PROPSHAFT SEAL REPLACEMENT?

Guess it was fun while it lasted!

 

[jebeebe]

Re: Lower Unit Question

Should I be worried to see new headgaskets. I did see some oil on the ground the first time I ran it, from the prop! URRRGGHH! Well, I'll replace the water pump, hopefully on Wednesday. Fill the case up with oil and see what I've got. Hopefully my water issue will be resolved, and the oil seepage was just build up as the engine has sat for who knows how long.

The boat has been a headache from day one. It's a 1973 Glassmaster 16ft. It had rotted floors, and a 1973 Evinrude that supposedly needed a power pack. A whole new ignition system(stator, powerpack, rectifier, coils, spark plugs, and battery,) and still no spark. I went ahead and replaced the floor, new carpet, seats, and lights. Found this Merc on ebay and paid $1300.00 for it. Now $300.00 later she still sits in the garage. I'm begginning to get really frustrated and my wife is running out of patience everytime I ask for her blessing on another part. Good looking motor though!

That oil coming from the prop could be black fuel/oil coming from the exaust.

 

[73merchead]

Re: Lower Unit Question

It's definitely gear oil! I think I screwed up and put oil in the gearcase without opening the vent screw. I hope I didn't screw the seal up!