15Hp Evinrude '76 - Appreciate your advice

[OptsyEagle]

Re: 15Hp Evinrude '76 - Appreciate your advice

Thanks a lot BK. That is a great list of answers to my questions. I never thought of the dremel tool method.

The manual has two arrows showing where the permatex is going. I thought is was to be sloshed all over the outside of the end of that crankcase head, but it looks like they want a little on the flats of the part that receives the driveshaft. I attached a better photo with the arrows showing there suggested area.

Did you put any permatex or 3M 847 in that area?

 

[bktheking]

Re: 15Hp Evinrude '76 - Appreciate your advice

I didn't when I rebuilt mine but if they call for it please do so.

 

[OptsyEagle]

Re: 15Hp Evinrude '76 - Appreciate your advice

Thanks BK.

On the seal replacement again, how did you insert the new seal in the crankcase head?

 

[bktheking]

Re: 15Hp Evinrude '76 - Appreciate your advice

Found a socket of the same diameter as the metal part of the seal then I tapped it in using the socket and a hammer.

 

[Rick.]

Re: 15Hp Evinrude '76 - Appreciate your advice

And when your all done get those NKG plugs out of the picture. LOL. Rick.

 

[OptsyEagle]

Re: 15Hp Evinrude '76 - Appreciate your advice

I am a little confused about the orientation of the upper water tube grommet. When I removed my exhaust tube it would appear that the top of the copper water tube was flush with the top of the exhaust tube.

I am not sure then, if I am supposed to put the top of the water tube into the groove of the grommet. This groove is in the center of the grommet. If I did this then, if the top of the water tube was flush with the top of the exhaust tube, then that would mean there would be about 1/4" of grommet material above the top of the exhaust tube. Should this material be stuffed into the hole in the powerhead. It doesn't look like it would fit.

The other option would be to ensure that the entire grommet is inside the hole in the exhaust tube. This would then place the top of the water tube about half-way in that same hole and the top of this water tube would not be flush with the top of the exhaust tube, in this configuration.

The last option I can see, would be to have some of the grommet below the hole in the exhaust tube, which would place the top of the water tube at the bottom of the hole in the exhaust tube. This again would not place the top of the water tube, flush with the top of the exhaust housing.

Please help. My manual has a picture also showing the top of the water tube flush with the top of the exhaust housing.

 

[OptsyEagle]

Re: 15Hp Evinrude '76 - Appreciate your advice

Anyone replaced one of these "upper water tube grommets. It seems like the edge of the water tube needs to go into the groove in the middle of the grommet. If I do this and place the water tube level with the exhaust tube, about 1/2 of the grommet will be sticking up above the exhaust tube. Is this the correct way? It seems to me this would be a problem when I go to bolt the exhaust tube back onto the powerhead.

 

[bktheking]

Re: 15Hp Evinrude '76 - Appreciate your advice

Yes this is correct, at least it has been on all my repairs of this grommet and I haven't had an issue.

 

[OptsyEagle]

Re: 15Hp Evinrude '76 - Appreciate your advice

BK, when you bolted on the exhaust tube, did the amount of grommet sticking up above the exhaust tube not keep the exhaust tube from sitting flat against the powerhead. I am puzzled as to where all this extra grommet material (1/4") goes when the exhaust housing is bolted up. It seems like it would spread out and perhaps get in between the exhaust housing and the powerhead. Or if it pushes the water tube down into the hole that it might be too low at the bottom for the water pump to fit in it.

What am I missing here?

 

[bktheking]

Re: 15Hp Evinrude '76 - Appreciate your advice

I just went to the garage and looked at a block I have sitting there. It isn't a 76 , I believe it is newer. The water inlet on the block is recessed, I believe the grommet was redesigned to fit in this recess for a better seal, does the 76 block you have have this recess?

 

[OptsyEagle]

Re: 15Hp Evinrude '76 - Appreciate your advice

No my recess is round all the way. That recess looks like it would mate up with the powerhead better, however.

I think I know where my confusion is coming from. I am getting pre-occupied with ensuring that the top of the copper tube is flush with the top of the exhaust housing, so that it is in the exact same position that it was in when I removed it, and therefore ensures a proper fit into the water pump. If the top copper tube is in the middle of the grommet and also at the top of the exhaust tube, about 0.200" of grommet will protrude above the exhaust housing. I see this creating a problem when bolting down the exhaust tube to the powerhead.

Now I am thinking, that they want me to have the entire grommet inside the exhaust tube hole, with the flange on the copper tube in the middle of that grommet. This would fit well, hold well and probably seal well, but would put the copper tube about 0.200" deeper into the water pump's grommet at the bottom. When I look at the pump assembly it appears that this should not cause a problem.

BK, do you remember if your upper grommet was completely pushed into the exhaust tube's cavity putting the top of your copper tube a little inset (about 0.200") from the top of the exhaust tube?

 

[bktheking]

Re: 15Hp Evinrude '76 - Appreciate your advice

That is the idea. There is a slot in the middle of the grommet where the lip of the water tube will go. Once seated in the exhaust tube a small amount of the grommet like you said will protrude giving you a tight seal. I know for a fact the that there was a protrusion, I've replaced those grommets more than once and the new design allows for it and I have never had any water flow issues once replaced. I understand your concern, who wants to pull the powerhead twice cause of a grommet issue.

I believe you posted the same question on AOMCI and I hate to say but I think the responder was wrong in saying "half the grommet is left unsupported in the exhaust tube". Bolt it up and see, there is quite an amount of support and I believe the new design is much better that the old one, it provides the same amount of support and allows for a better tube to powerhead seal. Once everything is bolted in place it shouldn't move, the powerhead doesn't move, nor does the lower unit so the issue of "support" doesn't really come into play, it's more of an issue of sealing vs support hence the redesign.

 

[OptsyEagle]

Re: 15Hp Evinrude '76 - Appreciate your advice

Thanks a lot BK. I really appreciate your advice.

 

[jmendoza]

Re: 15Hp Evinrude '76 - Appreciate your advice

The King is right on..this is exactly as it should be, the tubes flange goes in the upper grommets groove. In all actuality then the very upper inside diameter of the grommet will not have the tube wall in contact...maybe this was what was meant by the comment that it's unsupported. Anyway, it's pretty stiff so it wont be a problem for many years. Eventually they do get soft and break down, I have seen them collapse and restrict water flow, but you won't have this issue for at least 20 years with just seasonal use.

Be very careful if you replace the water pump grommet, the early engines with square exhaust tubes use the smaller profile grommet. The taller grommet for the pump is for later 15s with round exhaust. The taller grommet will seal against the hole in the bottom of the exhaust housing that the water tube pases through on the earlier models and prevent the housing from draining! So the bigger tall grommet(one of three supplied in the water pump kit) is for 15 round tube exhausts only! Some people have misstakenly posted on their site (Leroys Ramblings)that it does a better job of guiding the lower end of the water tube into the water pump...well it does, but if your engine used the small one , don't replace it with the big one.....been there, done that, learned the hard way.


One other thing, replace the upper mounts now as it's much easier, and a good pre-emptive strike, mine went bad right after fixing my powerhead, and caused me extra work I could have avoided. Repalce the foam seal ring for the lower cowl half too before bolting on the power head. Dip the powerhead and lower unit mounting bolts in OMC sealant or RTV so they don't corrode. You can get touch up paint from BRP in cans, still availlable and makes for a nice job. If yur local shop has the timing arm for setting the points, ask to borrow it and check the timimg. Re-synch the throttle arm to magneto cam setting, see manual. BTW, I use NGK B7-HS plugs, they work just fine and foul less than Champions or I would not use them (I troll quite a bit) Replace the upper crank seal too, now is the time, it will pop out if you tap one side with a brass punch, use a socket to press in the new one with the old one on top of the new one to act as a tool.

You have the best version of the 9.9/15 as it has points and is practically bullet proof. Later models had sucessively more plastic parts that break, and troublesome electronic ingnition "power packs". Mine 1975 has never left me stranded on the lake since I got it in 1978.

 

[OptsyEagle]

Re: 15Hp Evinrude '76 - Appreciate your advice

Well the powerhead is back on and the motor now works just great. I do not know how to thank everyone on this site. I certainly could not have fixed this motor without you. You guys are the best. Special thanks has to go out to Bktheking for his many prompt replies to my questions and of course themachinist for all his work pertaining to these motors.

I bought this motor for $50. It had no spark, and only half of a ground wire from being chewed up by a mouse. It's hood cover was also chewed up and after those things were all repaired, I found out that it's lower crankcase seal was toast making the bottom cylinder run very poorly.

I fixed the hood with a fibreglass repair kit. I added another ground wire, put on new points, condensers and new coils and changed the spark plugs. The old coils were working but were pretty rusted out and had some cracks in the insulation. I changed the rusted open thermostat and replaced the water pump impeller. I rebuilt the carb and changed the fuel hoses. Added a new head gasket after I inspected the cylinders. Lastly, I popped the powerhead, changed the lower crankcase seal, replaced the upper water grommet and inspected the reeds and changed their gaskets. My $50 motor is now about a $350 motor, but worth every penny.

I put her back together and she now purrs like a kitten. It pretty much starts on the 1st pull, it idles wonderfully, trolls like a turtle with no hesitation or missing and when you open up the throttle, she lifts my 14ft boat out of the water like it was as light as a beach ball.

I have attached a few pictures. The 1st picture is a before shot of the motor as I obtained it. The 2nd is a picture of it idling on my boat a few days ago. The 3rd shows it pushing me up the river with the water pump keeping her nice and cool (BK, I replaced the upper water grommet as you and jmendoza suggested, and just as you said, it worked great). The 4th picture is just another of it racing up the river. As Bktheking said on another post, these 15Hp motors really do have "crazy power".

 

[Rick.]

Re: 15Hp Evinrude '76 - Appreciate your advice

Good work. Glad to hear she is running like it was meant to run. You should be proud and I think you are. First motor I ever worked on was an 82 15 Evinrude and I still have it. Rick.