Nissan 3.5B2 outboard shift linkage access cover

[Richard19068]

Good morning (at least here on the west coast).

I have a 20 year old Nissan 3.5B2 two stroke 3.5 horse outboard. The one with neutral and foreward gears. It is the same as a Tohatsu 3.5B2. Never had a problem.

Yesterday while running it in a bucket to rinse out the sea water there was a fairly loud pop and the exhaust changed pitch. Apparently the shift linkage access cover blew off (and sank in the chuck). This is item 24 in the attached schematic (they call it " grommet 29-3"). All else seemed normal. No overheating and plenty of water coming out of the indicator hose.

Since I no longer have the cover I duct taped over the hole and restarted the engine. All seems fine. Runs and sounds fine

Now, while I wait for a new part to be shipped, does anybody have any insight as to why this cover might have blown off? Anything I should look for? There doesn't appear to be any way for enough pressure to build up in that section of the drive shaft housing or gear case to cause the cover to blow off. All the exhaust passages are clear.

Thanks.

 

[Rich Stidger]

I have the same engine and I also had the black cover come off. It was many years ago, and I don't recall the reason, but I also don't remember any ill effect. In my case I didn't lose the cover; I simply snapped it back on.
Sorry I can't be more helpful.

 

[Richard19068]

Actually Rich, that is helpful.

Good to know I'm not the only one that ever had it happen and good to know you had no recurring issues.

Thanks