Lower unit stuck, 1974 Merc 20hp

[DaubsNU1]

Water pump not "peeing" on the 1974 Mercury Thunderbolt 200 (20HP). 

 

I managed to get the two screws out...but the lower unit does not want to budge.

 

Knocked around with rubber mallet...no luck.

 

Manged to drive flat head screw driver between lower unit and open it up just a bit.  

 

Suggestions?

[Jig Man]

Bite the bullet.  Take it to a repair shop.

[Way2slow]

Sounds to me like you have missed some bolts and are trying to destroy the thing driving a screw drive into it.  I have never seen a lower unit only being held on by two screws/bolts.

Now, I will also say, if by chance to do get a the fasteners out, it's not uncommon for the drive shaft to be rusted into the crankshaft if it didn't get a good glob of grease put on it by the last person the took it off.

 

I will also suggest, you may not have a problem with the water pump if you are just basing it on the fact there is no water coming out the pee hole.  If it not running hot, might want to make sure the hole isn't clogged.

 

[WRB]

I believe the lower unit grease housing that contains the water pump has 4 bolts underside of the cavitation plate that holds unit onto the lower unit housing. As noted the drive shaft splines may be corroded together.

Sounds like you may have removed the grease drain screws. 

Suggest you go online a look at some vedios on how to do this.

Tom

[TnRiver46]

The tail waters I fish go up and down everyday and are littered with floating logs. I’ve hit plenty and had some L/Us stuck on pretty hard that needed “persuading”

[@reelChris]

Good explanation of getting the lower unit off a mercury 110 from the same era starting at 1:16.  Note his rubber mallet technique.  Sometimes, you need to use a piece of 2x4 and hit that with the mallet to persuade a stuck lower unit to come off.  Make sure you have something soft underneath it though, because oftentimes they'll come flying off after being hit. 

 

[813basstard]

I ain’t bright..

But when 1974 and rubber mallet are used in the same sentence, it ain’t good. 
 

Try one from let’s say the 90’s?

[DaubsNU1]

Lower unit is off!

 

There were two additional bolts that were semi hidden. Appreciate the suggestions. In the videos I watched the motor looked same as my 20hp, but the lower unit was different. 

 

Unit is off...now I'm struggling to get the impeller off the drive shaft...looks to be rusted on there.  I'm soaking with penetrating oil.  One problem solved...another problem comes up : ) 

[Big Hands]

If you have the serial number available, I would go to marine engine * to see the exploded view for your outboard. They have many of the parts available. That should give you an idea of what you can be a bit more forceful with, or not, depending on whether or not the replacement parts are available and if you can afford to buy them should you need to. 

 

I would think that the drive shaft would be stainless steel, so it may be corroded, but I doubt it is rusted. When you reinsert the lower unit back up into the motor, make sure to grease the splines on the drive shaft.

[DaubsNU1]

Dremel tool did the trick! I carefully ground things down until the water impeller broke free.  

 

Hit Marine Engine *, ordered parts...they should be here by Friday!

 

Good advice here...THANK YOU!

 

Side note: I called around to a few local marine repair shops in Eastern Nebraska...two didn't answer the phone.  One said he was so busy, not taking on new projects right now. One guy said he would replace my water impeller for $175...needed $100 deposit. I asked how he might get the impeller off and he scoffed at me, saying "I'm not telling you my trade secrets...if you want to youtube it, have a ball."  Ha! Saved myself a some $$ today. 

[@reelChris]

In the future, a cold chisel and a hammer usually go right through the brass center of the impeller.

[haggard]

I have a 1974 Evinrude 15hp 2-stroke with a lower unit that looks to be held on by two screws. It's a bit seized up and from what I've read it's time for a gear puller. There's a youtube video on it - maybe check it out.

 

[DaubsNU1]

Tested and worked.  Engine operating as normal..."peeing" water out almost imediately after start up. 

 

Fished yesterday, engine worked fantastically!

 

Only one issue to resolve...the mechanism that locks motor / keeps from tilting up in neutral and reverse...it's not latching. Hopefully I will have some time this week to look in to that.  

 

Killed it fishing yesterday...they bass were biting...I put 66 fish on the fishing log yesterday...all but three were small bass in the 9-12" size range.  Two crappie and one bluegill.  

[Alex from GA]

I have a '74 200 also and a '96 Merc 25.  I forgot what holds the 20 hp  but the 26 has a washer on the shift shaft that keeps it from coming out of the water in reverse.  When the lower unit is dropped the washer falls on the ground.  I learned this the hard way several years ago.

[DaubsNU1]

Thanks Alex. I got the locking mechanism fixed on Friday. Merc worked great today at the lake! Only caught 7 today...rough day...no wind, started at 6 AM / 56 degrees and 91% humidity...finished at 1 PM, 90 degrees.