sunk my 1979.5 merc 115. some help please

[beretta5spd]

to keep the story short, my 115 got sunk last tuesday. i was away from a shop and so I drained the pulled the plugs and drained the cylinders by turning it over, drained and refilled the fuel tanks, and then restarted it. note i did this out of the water without any earmuffs for a total of 8 minutes starting/stopping the engine and getting the idle down smooth.

i obviously destroyed my impeller which i knew would happen before I restarted it. i figured the impeller would be a cheap fix over letting the cylinders start to rust before I could get it back to my shop.

is there anything else I need to be aware of and check to make sure is ok?

and is there a guide to replacing the impeller on my boat somewhere online? ie where the bolts are to remove the lower unit, and how to unhook the throttle linkage to take the lower unit off?

any help would be greatly appreciated,
Dwight

 

[latin monkey]

Re: sunk my 1979.5 merc 115. some help please

there's alot of info on this site on how to do that

 

[beretta5spd]

Re: sunk my 1979.5 merc 115. some help please

that is true but I hate the search function on this site...unless I'm using it wrong. it searches threads containing "any" of the words used as opposed to searching for a thread with "all keywords."

i was hoping someone knew of a good thread in particular

 

[SeaKaye12]

Re: sunk my 1979.5 merc 115. some help please

Utube has some videos on water pump replacement. None that I've seen are 100% factual or all inclusive (IMHO) so I won't link to any one in particular, but if you search for Mercury WaterPump it should take you to a couple of good ones.

Chuck

 

[blazer01]

Re: sunk my 1979.5 merc 115. some help please

if you plan on keeping that engine i would see about buying a service manual for your engine

 

[blue90HP50]

Re: sunk my 1979.5 merc 115. some help please

Seems there were some good threads in March and April 2010. Irritate your wife and read the forum daily as a hobby.LOL Try the "similar thread" section at the bottom of the page. Good Luck. Blue. Put LU in forward. There's a bolt under the trim tab, one on each side, and one in front. LU should drop.

 

[79Merc80]

Re: sunk my 1979.5 merc 115. some help please

You don't have to do anything with the throttle linkage.

Here are some pictures of where the bolts are

 

[Chris1956]

Re: sunk my 1979.5 merc 115. some help please

You ran that motor for 8 minutes w/o water? Didn't it overheat?

Any service manual will have a reasonable procedure to change the waterpump impeller. Regardless of what the manual says, put the MerControl in neutral, and do not disconnect the shift cable. it is unnecessary.

 

[beretta5spd]

Re: sunk my 1979.5 merc 115. some help please

Thanks all for the replies....

@ Chris.... I sure hope it didn't overheat. It was still idling smooth. I've had 2 strokes overheat before unfortunately and it took a lot more than what I was doing to it. Also, I ran it on and off at idle for about 8 minutes total over the course of an hour, not straight.

I now realize it wasn't a smart thing to do...I'm having some fun replacing the impeller.....it melted nicely to say the least. But like I said my main focus was getting oil to the cylinders after it had been sunk and then sat overnight.

Thanks for the tip on the repair manual. I borrowed one from a friend and will have to pick one up for myself.

The impeller is being quite the pain to get off the driveshaft. I started to cut it off with a dremel. Is there anyone else out there that has had a similar experience? It will slide up and down a little bit on the driveshaft, and will slide side to side a little bit as well so it's not seized on....but it won't move up more than a quarter inch.

 

[Chris1956]

Re: sunk my 1979.5 merc 115. some help please

Sometimes the driveshafts get corroded and too fat for the impeller to pass. Sand it smooth. The impeller has a brass hub. Is that moving? You can crack it off with a hammer and chistle, use the dremel, and then the chistle to spilt it.

 

[beretta5spd]

Re: sunk my 1979.5 merc 115. some help please

old impeller is off.... new impeller is on! lower unit ready for reinstall.

it's being an absolute piece of garbage trying to get the lower unit
installed. what a ridiculous pain in the arse it's been. i'm taken two
stabs at it.... still doesn't want to go. not giving up yet though.
gonna give it another try tonight

 

[Chris1956]

Re: sunk my 1979.5 merc 115. some help please

The first time can be rough. After you have done it once, it will go much smoother.

OK, Gearcase and MerControl in neutral. Motor trimmed all the way up, wrap cowl and top cowl off. Grease the splines of the drive and shift shafts. If you operate in saltwater, lightly grease the entire driveshaft.

Shove gearcase into midsection. Install watertube into plastic guide tube. Push gearcase all the way up. Hold with right hand, and turn flywheel with left hand. Driveshaft will mate with crank splines. Now observe upper shift shaft position. Move it with needlenose plier to mate the lower shift shaft, if you can. It also helps to install that plastic casting into the midsection to hold the upper shift in the correct position. You may need to rock the throttle handle to make them mate.

Piece of pie!