I just purchased a 1993 mercury 115 hp outboard

[radiotoaster]

I just bought a 115 HP Mercury outboard 4 cylinder to replace an early 70's tower of power as the wiring is pretty shot. After I got it home I noticed a large hole in the driveshaft housing right above the lower unit. my question is, will this hole not allow the engine to run properly? I found a replacement housing yet not sure if I should purchase it before I install it on my boat and try to get it running. Any advice would be much appreciated. Picture of the damage is attached... Could this be repaired, JB weld? I am torn on putting more money in it before I even make sure it runs.

 

[racerone]

Just start the motor.-----Tape that hole over during the test run.

 

[roscoe]

That hole is really not a problem. Exhaust and cooling water will come out, no biggie.
Patch it or duct tape it if you like.

 

[1nebel0]

The motor is going to be loud since the exhaust will not be out of the water and not coming through your prop when on plane.... I would have a welder patch it..not a big deal and will quiet the motor back down.

 

[Texasmark]

My opinion is that someone deliberately cut the hole to access the shifting linkage at the lower unit interface. If the anti ventilation plate....the horizontal plate just below the hole, is in the slip stream (water coming out from behind the bottom of the boat) then ram water pressure MIGHT be a problem because the powerhead engine exhaust and cooling water are attempting to leave the powerhead and exit the prop hub. A large volume of water, under ram pressure, could really confuse things. Not sure it it would be enough to get back to the engine but who knows, would surely inhibit the ability of the engine to exhaust correctly.

Get a soda pop can and cut a suitable cover for it. Take some sandpaper and rough up one side of the alum can and the associated surface of the lower unit around the hole. Go to an auto parts store, WM, or wherever and get some JB Weld, or Metal filled Devcon and glue the shield over the hole. Then forget about it.

 

[Faztbullet]

You will need a midsection not a lower unit housing if you want to replace this. I have seen this type of damage before and its from bouncing on a motor toter device,The easiest fix is to have a thin plate(patch) welded over hole...

 

[Texasmark]

You will need a midsection not a lower unit housing if you want to replace this. I have seen this type of damage before and its from bouncing on a motor toter device,The easiest fix is to have a thin plate(patch) welded over hole...

Well that makes sense. Interesting how clean the lines were rather than spider web fragmented random chunks missing.

 

[radiotoaster]

Hey guys thank you for all of the insight!! I will plug up that hole in the mid section. Now that the weather has warmed up and I was able to borrow an engine hoist and build a stand. I got the motor on a stand and started "tinkering". It always sounds like a great idea in the beginning and now there seems to be hurdles at every step. I am not sure if anyone is interested but I am going to just keep the progress of this project updated here. First, I replaced some bad oil and fuel lines. Then I hooked up the battery, when I hit turned key the starter spun but was weak to the point it would not pop the gear up. I read that it could be due to a battery or bad cables/ connections. I sanded the connections and tested the battery, same outcome. I cracked open the start and it appeared to be a mess, the magnets on the casing were cracked and chipped the bottom half of the armature was rusted/ charred, and the center pole was badly pitted. So I ordered an after market starter. Furthermore the motor is missing a voltage regulator/ rectifier. This one should be fun, I will post an update once I get the starter. Are the elcheapo voltage regulator/ rectifiers on ebay worth their weight in dust or do I need to hand over atleast a $100 for a Sierra or OEM part? Again I really appreciate the feedback and encouragement.

P.S. Also when I turn the key there is a "beep" is this a warning "about to blow" beep or a "I am about to turn over" beep - my 1967 tower of power doesn't beep.

 

[Texasmark]

The beep you hear when you turn on the ignition switch is there to tell you that your low oil (in your engine mounted tank......intermittent beep when low) or your engine over temp (solid alarm when engine temp is above 195F) systems are working. Your tower had no thermostat (143F), self contained oil, pre-mix variable ratio (80:1 at idle moving up to 50:1 at the higher speeds) internal oiling system, and low oil or over temp warning (195F) circuitry.

I think that you would be wise to invest in a manual. You can "rent time" from this site with the Seloc manuals which I have done and works just fine. Go to the top of this page and look in Boat Parts and Accessories for access to Seloc manuals. You have immediate access and the rental fee is much less than buying a manual plus it's easy to walk through the pages you require; nicely indexed. Some engines have just rectifiers, and some regulators also. Most larger engines have rectifier regulators. They sell them on this site too and with the manual you should have no problem getting the right one.

 

[radiotoaster]

Thank you Texasmark it has been some time and I finally took off the tower of power put the 93 motor on the boat. I put on the new controls and installed a new trim pump as the other was completely seized up. Two nights ago, we had the trim going and I changed the lower end gear oil. We left the motor for about 30 minutes and when I came back outside the alarm horn was blaring, and I realized I left the key in the "on" position. I turned it off and messed with the float sensor in the oil reservoir. Last night my brother and I started the motor for the first time in a buck of water, the alarm initially stayed off. The motor started right away (pretty cool) then it died (not cool) we played with it for a 15 minutes where it would run for 10-15 seconds then conk out. At some point the alarm came on again as a constant. Also the motor stopped starting up (really not cool). Upon further inspection when we pulled the plugs there was no spark in any of the 4 cylinders. Also as a note through out this 15 minutes of the motor running and stopping there was no water exiting the tell tale. This morning I replaced the ignition switch and still no spark. I disconnected the overheat sensor and the low oil sensor and

 

[radiotoaster]

sorry for the repost but the first one was missing information

Thank you Texasmark it has been some time and I finally took off the tower of power put the 93 motor on the boat. I put on the new controls and installed a new trim pump as the other was completely seized up. Two nights ago, we had the trim going and I changed the lower end gear oil. We left the motor for about 30 minutes and when I came back outside the alarm horn was blaring, and I realized I left the key in the "on" position. I turned it off and messed with the float sensor in the oil reservoir. Last night my brother and I started the motor for the first time in a buck of water, the alarm initially stayed off. The motor started right away (pretty cool) then it died (not cool) we played with it for a 15 minutes where it would run for 10-15 seconds then conk out. At some point the alarm came on again as a constant. Also the motor stopped starting up (really not cool). Upon further inspection when we pulled the plugs there was no spark in any of the 4 cylinders. Also as a note through out this 15 minutes of the motor running and stopping there was no water exiting the tell tale. This morning I replaced the ignition switch and still no spark. I disconnected the overheat sensor and the low oil sensor and warning sound still on so assuming the warning module is bad. I am not exactly sure what I should look for on the no spark? I hear it can be the trigger, stator or switch box as I have no spark in any of the cylinders. Any help would be much appreciated.
Thanks for looking and happy fourth!