"It was as easy as some of you
"It was as easy as some of you guys said it would be. Thanks for the advise and direction. I thought I would leave a few tips and hints that stumped me a bit in the install process. It seems with most forums we get the information we need and never a follow up and "how it worked" responses.
The impeller replacement.....
Found the kit on amazon.com for a whole 13.88. That’s for the pump and impeller kit. The mercury dealer here in Norman OK charges 49.99. Worth the two day wait if you don't need to be on the water tomorrow.
Mine had two 5/8 nuts in the front sides to take off and 2 9/16 in the rear. The side nuts are height sensitive so going back on you must slide the washer and nut into place prior to pushing the prop unit completely together.
I used a soft rubber mallet to gently tap the unit apart. Mine may have been the original impeller and had never been broken apart.
I had no fins left on the sprocket and the rubber was cracked in numerous places.
The unit looks like a small cell phone with the crank shaft protruding out of it. it had four 7/16 nuts only snug fit down on the cover. Its plastic so don't break it. remove those and you will find two gaskets and a metal plate(replace as you remove them/remember how it goes together/I used a blue permanent marker)
I got stumped here. with no manual and nothing to reference I wasn't sure which end of the shaft was going to allow the parts to slide off. The top of the shaft seemed tapered and to wide and the bottom had no set screw or sleeve to remove the shaft out of. After cleaning the unit I found that it wasn't tapered at all. It had a two piece stop that slides off the top and made for an easy remove and install of the new parts. My new pump came with two or three parts that were not for my system so watch your parts and don’t get confused. Never a good felling when you take something apart and have a hand full of "what the hells". The new housing also had a two parts pre installed, use common sense and time, even though it is written on the head of the engine its not rocket science.
The new impeller seemed to be a puzzle. The housing is maybe 2" in diameter and the fins on the impellar are a stiff 21/2. I had to hold the housing in a leather glove for support and twist it into the housing slowly. This is the point it just didn't seem right. I read on a couple of other posts not to grease the fins. Take your time and get all the fins going in the same direction. That will center it on the shaft and allow the set posts and bolts to line up. Yep this is where my confidence level dipped a bit. Also look at the crank shat and see where the "key" is aligned. I had to take out the impellar(pain) and reinstall it to get them to line up properly on the shaft. Approximately 1/3 of a install turn pressing the impellar into the housing. I didn't want to spin the shaft in any way not knowing its impact.
Mine didn't have any gasket sealer on it and appeared to make a good fit so I didn't apply any.
Prior to starting the project I made certain I was in neutral and duct taped the prop to the housing and marked the shafts(crank and gear) so as not to get them out of sorts on reinstall. I had one hell of a time on remount. I was 3/4 of an inch out and figured out it was the gear splines not matching up. The bolts, exhaust, crank shaft, some other tube that I have no clue what is, and the gear cable all have to line up. This is where I enlisted the help of a neighbor. I had the motor unit in the down position and the bottom resting on a floor jack. I just didn't have enough hands to keep it all aligned and gently slide it together. after a good 45 minutes of failed attempts, I realized the splines for the gear cable could be wiggled from the cable out side of the housing. After that it was a cake walk. It seated up perfectly and took it to the boat ramp to see if this was a good idea or not.
Happy to report the stream looks like a two year old after 3 juice boxes or me and six pack. Total time from start to finish about 3 hours (I do a lot of fit and refit and "what the hell is that", so it would take a mechanic an hour tops.
So there is my story of the impeller installation on a 78 model 402 40 hp mercury. I'm not a pro by any stretch so if you have some mechanical skill you can do this. The dealer near me was going to charge 150.00 plus parts 49.99. So I just saved around 180.00.
Feel free to add or reply to this post. Hope it can help someone that is going to attempt it.
Hammer"
"It was as easy as some of you guys said it would be. Thanks for the advise and direction. I thought I would leave a few tips and hints that stumped me a bit in the install process. It seems with most forums we get the information we need and never a follow up and "how it worked" responses.
The impeller replacement.....
Found the kit on amazon.com for a whole 13.88. That’s for the pump and impeller kit. The mercury dealer here in Norman OK charges 49.99. Worth the two day wait if you don't need to be on the water tomorrow.
Mine had two 5/8 nuts in the front sides to take off and 2 9/16 in the rear. The side nuts are height sensitive so going back on you must slide the washer and nut into place prior to pushing the prop unit completely together.
I used a soft rubber mallet to gently tap the unit apart. Mine may have been the original impeller and had never been broken apart.
I had no fins left on the sprocket and the rubber was cracked in numerous places.
The unit looks like a small cell phone with the crank shaft protruding out of it. it had four 7/16 nuts only snug fit down on the cover. Its plastic so don't break it. remove those and you will find two gaskets and a metal plate(replace as you remove them/remember how it goes together/I used a blue permanent marker)
I got stumped here. with no manual and nothing to reference I wasn't sure which end of the shaft was going to allow the parts to slide off. The top of the shaft seemed tapered and to wide and the bottom had no set screw or sleeve to remove the shaft out of. After cleaning the unit I found that it wasn't tapered at all. It had a two piece stop that slides off the top and made for an easy remove and install of the new parts. My new pump came with two or three parts that were not for my system so watch your parts and don’t get confused. Never a good felling when you take something apart and have a hand full of "what the hells". The new housing also had a two parts pre installed, use common sense and time, even though it is written on the head of the engine its not rocket science.
The new impeller seemed to be a puzzle. The housing is maybe 2" in diameter and the fins on the impellar are a stiff 21/2. I had to hold the housing in a leather glove for support and twist it into the housing slowly. This is the point it just didn't seem right. I read on a couple of other posts not to grease the fins. Take your time and get all the fins going in the same direction. That will center it on the shaft and allow the set posts and bolts to line up. Yep this is where my confidence level dipped a bit. Also look at the crank shat and see where the "key" is aligned. I had to take out the impellar(pain) and reinstall it to get them to line up properly on the shaft. Approximately 1/3 of a install turn pressing the impellar into the housing. I didn't want to spin the shaft in any way not knowing its impact.
Mine didn't have any gasket sealer on it and appeared to make a good fit so I didn't apply any.
Prior to starting the project I made certain I was in neutral and duct taped the prop to the housing and marked the shafts(crank and gear) so as not to get them out of sorts on reinstall. I had one hell of a time on remount. I was 3/4 of an inch out and figured out it was the gear splines not matching up. The bolts, exhaust, crank shaft, some other tube that I have no clue what is, and the gear cable all have to line up. This is where I enlisted the help of a neighbor. I had the motor unit in the down position and the bottom resting on a floor jack. I just didn't have enough hands to keep it all aligned and gently slide it together. after a good 45 minutes of failed attempts, I realized the splines for the gear cable could be wiggled from the cable out side of the housing. After that it was a cake walk. It seated up perfectly and took it to the boat ramp to see if this was a good idea or not.
Happy to report the stream looks like a two year old after 3 juice boxes or me and six pack. Total time from start to finish about 3 hours (I do a lot of fit and refit and "what the hell is that", so it would take a mechanic an hour tops.
So there is my story of the impeller installation on a 78 model 402 40 hp mercury. I'm not a pro by any stretch so if you have some mechanical skill you can do this. The dealer near me was going to charge 150.00 plus parts 49.99. So I just saved around 180.00.
Feel free to add or reply to this post. Hope it can help someone that is going to attempt it.
Hammer"
