Logo
FULL SITE MENU

71 9.5 Sportwin Exhaust Seal/Boot

S

Sam110

Regular Contributor
Back again guys with another "issue" on this 9.5 Sportwin. I am told I likely have a bad exhaust boot seal causing a lack of power while running with the engine cover on. If I remove the engine cover it will rev up fine. That being the likely place to start and having found a "almost new" exhaust boot on Ebay (discontinued in '84 !) I'm looking for some instruction on where to / HOW TO access this part of the motor before starting. I've searched the forum and YouTube found several threads but no video addressing the issue but not with the 'specifics' I'm hoping to find.

Can anyone provide a link to instructions or possibly a video on replacing this 'boot'? My service manual is really vague and no help to me.
 
We used to drill holes in the front and back of the hood to get air in and exhaust out. Saved all that other expense and it worked.
 
Boobie said:
We used to drill holes in the front and back of the hood to get air in and exhaust out. Saved all that other expense and it worked.
Click to expand...

I did drill holes under the lift handle but it still dosen't give it sufficient 'clean air' to get up to full RPM. I've come up with a boot that's in great shape so I suppose I'll be getting at it when the weather goes to the dogs. For now I run it with the hood off. I was hoping someone could post a link to a step by step or a video before I get started.
 
Thanks Kim. I presume what needs replaced is the large rubber 'boot' like seal on the exhaust housing. I have obtained a good one (good, bad, or indifferent) for replacement yet I have not disassembled the motor to actually inspect the one thats currently on the motor. Not aware of the "bellows" part you are referring to unless its the exhaust hose where water is pumped out. It is in good shape. I suppose there may be other causes for my lack of RPM's while the engine cover is on but this main exhaust housing seal /'boot' seems like a likely cause.
 
The small bellows type hose is the exhaust relief and also it should spray water at slow speeds. The lower seal is usually damaged by bad motor mounts like was mentioned above just grab the gearbox and manhandle it if there is alot of movement you need to replace the bad mount/s while you have it apart. Just take your time taking it apart one of those cordless 1/4 inch impact drivers are nice for vibrating the old bolts out. It could also be a leaking exhaust cover gasket blowing burnt gasses in the cowl reducing oxygen to the motor. On very rare occasions the gasket between the powerhead and the exhaust housing could leak also especially if someone used silicone. Never use silicone anywhere on a outboard motor period. Permatex aviation will never let you down.
 
I don't see any obvious evidence that there has been any previous motor work done on this engine. I'll use a pump spray bottle of soapy water and spray those ares and see what may show up. Twisting on the gearbox housing does reveal some back and forth play, maybe 3/8" or so with some rubber in metal 'squeak' as it moves so I guess a motor mount is in order. The cordless impact driver I have. Once I check for leaks with the soapy water I'll get the project started.

As an after thought; does a SELOC manual go into this sort of repair? I suppose having one around for such things would give me an advantage but the one for this yr. 9.5 includes so many other motors that I'm sceptical of just how useful it might be?

Thanks Kim
 
If you don't mind my saying so, I think you have the cart way out in front of the horse. How did you come up with the conclusion that the boot is bad? Maybe it is and maybe it isn't.

#1 First question I gotta ask--Where are you running this motor? Is it on a boat on the lake or is it in a barrel? If it is in a barrel, you are deceiving yourself. No 9.5 will run in a barrel with the hood on. Not even when they were new.

#2. OK if it is on a boat on the lake, the boot is just one of several ways smoke gets under the hood. Two more are the boot on the shift rod, and the seal on top of the water pump. Easiest to check is the water pump.

3rdly, the boot you are talking about can cause smoke inhallation while running at slow speeds or at dockside. However at full speed (on a boat) the smoke is left far behind in the wake and does not rise up through the boot.

4. Assuming you are going in to replace the boot, do the one on the shift rod also. It is a very common route for smoke intrusion.

5. If you suspect the motor mount is bad, grab hold of the flywheel (not running, duh) and see if you can push/pull the motor fore and aft in the shell. A rubbery feel is normal, gross fore and aft movement is not. A broken mount causes other problems, but not smoke.

6. All of these issues (except the water pump) require shucking the motor out of the outer shell. An extremely intimidating job for most novices. A factory service manual is almost a must-have.

I've done these jobs many times and know what you are getting yourself into. Hopefully, maybe you are running it in a barrel and don't even have a problem.
 
Gator I don't mind you saying so at all. In fact it's not unlike me to get out ahead of myself at times. I would rather not to have to do anything any more than necessary but I would also like to run my motor with the engine cover on. I was advised by another member (?) that this indicates a bad exhaust housing seal / boot. Made sense to me.

To give you some answers:
#1 Yes I'm running this motor on the boat in the river.
#2 I replaced the impeller and water tube grommet this spring. I didn't know to check it or that it could be a problem. Now I know to ck it.
#3 Full speed is when the motor exhibits its sluggishness until you remove the motor cover then it will pick up nicely.
#4 Once I determine where this shift rod boot is (I see it in the diagram) I'll inspect it, however they are no longer available (yikes).
#5 As for the motor mount test, fore and aft I would guess they are good, hardly any movement at all. (good news)
#6 I do have a Evinrude service manual but it doesn't go into much detail on this repair.
 
#2. There is a seal and support ring on top of the water pump housing. If it is missing, exhaust smoke travels up through the drive shaft isolation tube and out a vent hole at the top--which is under the hood.

#4 Torn shift rod boot allows exhaust to escape out the same vent hole. 309631 nymarine.ca makes reproductions. http://www.nymarine.ca/grommets.htm
 
Well, it took some time waiting on parts but I finally got back to the task of opening up the shell halves to determine the cause of an exhaust leak. In doing so I found that the exhaust housing seal (lg seal around outside of exhaust leg) was deformed. When last assembled it got hung up on one of the support structures of the shell half and put me in mind of a snarling dog or one who's upper lip was stuck to its teeth on one side which was a big contributing factor to the exhaust leaking. The shift rod boot was also torn however all engine mounts and the shell halve mounts were in excellent shape. I've replaced the upper shift rod seal, the shift rod boot and exhaust leg seal and reassembled it. The drive shaft isolation tube seal on top of the water pump was in good shape. I test ran it tonight in a bbl to assure everything went back together as it should and it seemed to run great! Perhaps tomorrow I'll get it on the river.

Thanks to all who contributed guidance and resources to 'Get-er-Done'.
 
Back
Top