Motor dies when the engine cover is put on.

[o/b tech]

I have a 1965, 9.5hp Evinrude, that when the motor cover is put on, even half way, it starts to slow down, stumble and eventualy quite. The base gasket area looks good and no apparent leaks. The big rubber seal, low in the belly-pans, also appears to be in place. It's as if it is getting exhaust gas from somewhere but can't see where. I'm going to replace the rubber seal today and hopefully this works. Any other ideas would be greatly appreciated

 

[F_R]

Re: Motor dies when the engine cover is put on.

Aha!! I've been waiting for somebody to ask that question. There are two other things which cause that problem...big time.

1. There is a rubber seal on top of the water pump housing, with a support ring inside. If that seal is gone, smoke goes up thru the drive shaft tube and comes out a vent hole at the top, which is under the hood. The seal often gets left out when the lower unit has been removed. (Some of those left-over parts that you "don't need").
2. There is a rubber bellows-type boot around the shift rod, where it and the water tube go up thru the exhaust housing. The rubber deteriates and tears and smoke goes up through there and out through the same vent hole already mentioned. The killer is that the boot is no longer made. It so happens that I am working on an alternate cure which is outrageously simple and simple to install, 15 minutes. I have samples out to be tested in the field at this point.

 

[o/b tech]

Re: Motor dies when the engine cover is put on.

Aha!! I've been waiting for somebody to ask that question. There are two other things which cause that problem...big time.

1. There is a rubber seal on top of the water pump housing, with a support ring inside. If that seal is gone, smoke goes up thru the drive shaft tube and comes out a vent hole at the top, which is under the hood. The seal often gets left out when the lower unit has been removed. (Some of those left-over parts that you "don't need").
2. There is a rubber bellows-type boot around the shift rod, where it and the water tube go up thru the exhaust housing. The rubber deteriates and tears and smoke goes up through there and out through the same vent hole already mentioned. The killer is that the boot is no longer made. It so happens that I am working on an alternate cure which is outrageously simple and simple to install, 15 minutes. I have samples out to be tested in the field at this point.

 

[o/b tech]

Re: Motor dies when the engine cover is put on.

I will check that out and please let me know how the fix works.

 

[ezeke]

Re: Motor dies when the engine cover is put on.

F R, Do you have a source for the drive shaft/ impeller housing seal - part #309607?

I've had a couple of instances where the exhaust relief hose has broken along the inside seams where it is difficult to see. With the engine running, cover the outlet briefly to see if it will hold the pressure.

 

[F_R]

Re: Motor dies when the engine cover is put on.

Until just now, I didn't realize 309607 is obsolete too. BRP sure seems anxious to get all those motors junked.

 

[o/b tech]

Re: Motor dies when the engine cover is put on.

I just installed the new rubber seal and ran the motor again. It does the same thing. When I pulled the lower unit off, it did not have the seal, 309607. This is strange considering that the w/p kit that I put on did not have it in the box. The gearcase did not have it on there prior to putting the kit on.

I didn't see the rubber boot on the shift shaft when I had the motor appart?

Is there any way of getting The part 309607, or will another seal work?

Thanks guys.

 

[o/b tech]

Re: Motor dies when the engine cover is put on.

I forgot to mention that the exhaust is coming from the front of the motor. As soon as the motor cover is clipped into the front slot can see a small amount of exhaust smoke being drawn towards the carb.

Thanks again for any ideas, as I've been fighting with this for a while now.

 

[Nythorn]

Re: Motor dies when the engine cover is put on.

Hi Guys, I am a brand new member here and joined seeking help for my 1966 Sportwin 9.5, model #9622A. I joined here to make my first post pleading for help because the motor runs great at his place in a barrel but once on the boat and in the water it runs like CRAP! Reading this post I now wonder if fresh air intake is my problem as well. It has new coils, a rebuilt carb, new points and condensor, rebuilt carb and waterpump all done 2 years ago with only one use since the work was done. It starts great, pumps water nicely and runs great in a barrel as it was originally demonstrated to me. Now after two "motor"boat "rides" and two return trips to the guy I bought the motor from and reading this thread I am wondering if I have found the problem and at the same time ask myself if I have purchased a boat anchor due to the lack of seals that I may be missing? Funny, today when I left the guy I bought the motor from he told me to try running the motor with the hood off and see if the problem was cured. Come to think of it, every time I have seen this thing run like a raped ape it had the hood off... If the seals aren't available would it help to drill a couple of "breather" holes into the cowl to let it breathe?

 

[o/b tech]

Re: Motor dies when the engine cover is put on.

I tried that at the back of the motor cover, under the grab handle. Unfortunately it didn't make a diiference as the clean air will not reach the carb in time. Drilling a hole anywhere else may allow water to get into the engine. My 9.5 runs great with the motor cover off as well.

hopefully we can get some answers to our problems.

Thanks.

 

[Nythorn]

Re: Motor dies when the engine cover is put on.

o/b tech, What about holes on the side of the cowl nice and close to the carb intake? I don't know about you but I can't see that much water getting splashed up the sides of the motor?

Can anyone here please tell me what the correct spark plug is for this motor?

 

[o/b tech]

Re: Motor dies when the engine cover is put on.

The correct spark plug for the motor is a champion J4J.

I've thought about making a snorkel for the carb, thru the cover,directly above the carb. It would have to be angled back so that the rain could not get in. Just have to figure out a foam gasket that will be fexible, to stay in contact with the carb,as it moves around under the stationary engine cover. As you can see, I've been dealing with this problem for a while.:/

 

[stl]

Re: Motor dies when the engine cover is put on.

Do a search on this forum about this problem. This problem has been discussed many times on this forum. There have been some solutioms on here that seem to work. I don't have a very good understanding of what the schematics are. But some guys talk about cooking up some sort of air scoop, that seems to work.. I actually own a 1965 9.5 hp Johnson That I have had no problems with. The motor runs so strong that I can't think if getting rid of it. If it happens to my motor, then i will deal with it. I think it would be pretty cool if Joe or someone could provide a simplified explanation of why this happens to the 9.5s. What was the actual defect that made the 9.5 do this. It is funny that you only hear about from the 9.5.

 

[F_R]

Re: Motor dies when the engine cover is put on.

OK, guys, first the seal doesn't come with the water pump kit. When you threw away the old housing, you threw away the seal too. It's a special seal, unlike anything else on the market. It's worth a try to see if Sea-Way Marine has any of them. http://www.sea-way.com/index If the seal is not in there, you have found at least half of the problem, maybe all of it. Yes the smoke comes up from a hole out of sight in the front of the exhaust housing, near where the shifter goes down.

In dealing with motors that run in boxes on sailboats, I have tried a number of snorkle schemes. Never had any success. But what have you to lose? Except a hole in the hood.

The shift rod boot is above the plate that you see if you look up where the shift rod and water tube disappear into the exhaust housing from below. You can't see the boot from below. Don't be removing the plate unless you have a new boot.

If anybody wants to try my solution to a torn shift rod boot, e-mail me at gatorsnfrogs@verizon.net and we can talk about it.

 

[F_R]

Re: Motor dies when the engine cover is put on.

To stl from St Louis....You asked for a simplified explanation. Well I'm pretty simple-minded. The drive shaft runs in a separate chamber in the exhaust housing, sealed from the water pump up to the powerhead. It is a good deal in that it keeps the exhaust and spent cooling water away from the lower main bearing of the powerhead.....otherwise, exposure is death to the seal and water can enter and destroy the powerhead.

To maintain the integrity of that sealed drive shaft chamber, a seal is used where the water pump and exhaust housing meet. Another seal, a bellows-type boot is used around the shift rod and water tube where they enter the exhaust housing. If any of these seals are breached, exhaust smoke is allowed to enter the drive shaft chamber.

Water escapes from the water pump housing, around the drive shaft, a normal and intended function. That water is drained off through a hole or holes in the lower part of the housing. And a vent hole is provided at the top of the housing. It is through this vent hole that the unwanted smoke comes. If it were not for the water drain and vent hole, water escaping from the pump would fill the chamber and be forced into the powerhead.

While the 9.5 has gained fame for getting smoke under the hood, it is not the only one. The 1960s-vintage 35-40hp and v-4 models with the double housing "Super Quiet" style all have a smoke seal on top of the water pump and will do the same thing if it is missing.

Hope this helps.

 

[Nythorn]

Re: Motor dies when the engine cover is put on.

F R, I am going to make the assumption that my motor has this problem. You wouldn't by chance have the part numbers for the seals mentioned would you?

 

[F_R]

Re: Motor dies when the engine cover is put on.

The seal on top of the water pump is 309607. There is a support ring that goes inside it, 309583. The shift rod boot is 309631

 

[Nythorn]

Re: Motor dies when the engine cover is put on.

Thanks F R, I'll go searching now!

 

[pvanness]

Re: Motor dies when the engine cover is put on.

Hi, I'm the guy who sold NYTHORN his 9.5. I was able to
locate and purchase 2 of the 309607 water pump seals today at my local "older" dealer. The 309583 seal washer is still a good number in the BMI price book and I
picked up one of them also. The 309631 shift rod boot is another story! I'd be interested in hearing about the "fix" for it that O/b tech mentioned in an earlier post.
Thanks. Peter

 

[o/b tech]

Re: Motor dies when the engine cover is put on.

Thanks for all your help guys. I'm going to be looking around town in the next couple of days to try and track down these very important parts. If I don't have any success with the shift boot, I would like to contact you at your e-mail address, F R.