Tohatsu M8B shifter cam...and I'm an idiot.

[laurentide]

I was doing an impeller replacement today, and foolishly pulled the shifter cam out of the lower unit when I dropped it. Yep, should've used the shop manual...I didn't. It doesn't just "go back in," correct? It seems like I'm going to need some kind of puller tool here for the prop shaft, but before I get deeper into fixing my mistake I figured I'd see if there was any other way to get that cam back in. Thanks!

 

[pvanv]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

First, don't beat yourself up. These things can and do happen.

Secondly, you might get lucky... I have before... align the flat of the cam aft (towards the prop, and wiggle-wiggle as you push down, to see if you can get it past the push rod (which is in the end of the prop shaft, and is spring loaded). I am usually able to pop it back in that way. You will be fighting the spring load of the push rod, so don't be afraid to push down firmly. Then reinstall the cam rod bushing.

As a last resort, and the way the factory would have you disassemble the LU... remove the prop, then pull the 2 bolts that retain the prop shaft housing to the LU, and extract the housing a quarter to a half of an inch. That's all it takes. But be forewarned that the prop shaft housing "spool" may be a bit recalcitrant. Do not do anything rash, that can break an ear off of that housing, or you will be buying a new one and installing a new LU seal kit. If you end up accidentally completely removing the prop shaft housing (complete with the shaft and the R gear), be careful not to drop the push rod and the clutch spring retainer.

 

[laurentide]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

Paul, thanks very much for that reply. I'll try working the cam back in front of the push rod. It does seem like the cam's shape should facilitate this. I haven't tried using much force yet. This engine has seen some salt, I think, so I'd much rather get it back in this way than fight corrosion. Thanks again. Great info.

 

[laurentide]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

Got it in. Awesome help, man. I was trying to do it with the shift linkage still attached to the upper leg. Once that was disassembled the rod pushed right in. Thanks.

 

[laurentide]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

I've got another question about his engine, and I'm hoping it's cool to just piggyback on this existing thread. When I was pulling the drive shaft out the first time with the lower unit, a couple of cylindrical pieces of broken metal fell out of the upper leg. It looked like it could have been part of maybe a 3/4" pipe or conduit. So I obviously know this is not good, but I already had it apart and put the impeller in and, with some help here, got it back together.

I started it up today in a barrel, and the lower cowling almost immediately fills up with water. There's a little coming out of the telltale, but most of it is steadily spraying out of the base of the block on the port side, right in front of the exhaust manifold. So I'm guessing that the broken pipe has something to do with this, but I have no clue. Is there a base gasket that can be replaced?

This was a $40 CL purchase a few weeks ago. It was seized and had been sitting for years, so I have no history with it. It's also pretty corroded, and I'm guessing was a saltwater engine at some point. Cutting bait wouldn't be the worst thing in the world, but I'd love to diagnose this problem before I give up on it.

Thanks!

EDIT: I got it started two weeks ago after a Mystery Oil treatment, and it wasn't peeing at all, nor was the leak occurring. All I've done is replace the impeller, gear oil and plugs...and break something made of metal. It runs great, by the way...but probably not so much when the whole cowling fills with water.

EDIT #2: Right below the leak, on the underside of the cowling directly behind where the shift rod exits, there is exhaust coming out with some water.

 

[Sea Rider]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

If you have removed head from base, will need to install a new base gasket to seal head properly against base (pan) or you will see water flooding there. Torque well all lower head bolts..

Probably lower water tube it's not inserted properly on water pump, have a corroded, broken water tube, or have a severe base gasket issue to achieve poor peeing.

Happy Boating

 

[laurentide]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

^^Thanks SR.

 

[laurentide]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

If you have removed head from base, will need to install a new base gasket to seal head properly against base (pan) or you will see water flooding there. Torque well all lower head bolts..

Probably lower water tube it's not inserted properly on water pump, have a corroded water tube, or have a severe base gasket issue to have poor peeing.

Happy Boating

I'm thinking the bolded is my issue. It's really pouring out of there...it fills the cowling in 30 seconds, even with the drains. Thanks for the reply and info.

 

[laurentide]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

Would part "23" in this diagram be the correct gasket?

 

[TOHATSU GURU]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

23 is the base gasket and if someone worked on the engine before you got it and was a complete moron that may be the problem. However, since the thing was seized and metal is falling out of it, it is just as likely that the block or base plate has been destroyed. If that's the case the cost of the parts to fix it will exceed the value of the engine...

After almost 30 years of production the 40 C is scheduled to be taken out of production so it's about to become a dinosaur.

 

[laurentide]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

Thanks, Guru. This thing is just going to be a kicker if I can get it working right, so I'm not putting any money into it. I'll try to pull the powerhead and see what's going on down there. It'll be kind of a shame if it's shot...it's a great runner for an old, very neglected engine. I guess best case scenario would be to get it going with a $6 gasket and then wait 'till the parts dry up completely.

 

[pvanv]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

Andy,

Pull the power head, and inspect the setup. Might just be a base gasket. But it could be a broken casting, etc. Once you inspect the carnage, you can make a decision as to whether it's worth your while to continue with the repair. There are still lots of the M8B's running, as they are almost indestructible, and are the lightest in their class. Eventually, corrosion kills them.

 

[Sea Rider]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

Might be thinking an idiot pulled that head out from base, broke the gasket which is cardbord type (not metal), aligned broken gasket, torqued head back and thouth that was it, probably wasn't aware the pan was flooding.

This happened to me once trying to sit and old, dried, broken 5 HP base gasket, the flooding was so huge you could keep living bait there. Check you don't have water leaking gasket issues with crannkcase's right side (exhaust gaskets N? 13) re torque, change if needed.

Happy Boating

 

[laurentide]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

Paul, you got it...it's a broken casting. I don't think there's a fix for it, either, as the whole piece that sits under the front part of the gasket is gone. All the metal on this thing is very weak at this point, so I think I'm going to move on to another cheap motor. If I had the piece, I'd at least try to jb weld it, but I don't think there's any way I could fab the missing material. It's too bad, as the thing still runs and shifts like a champ.

No biggie...a learning experience and $60+.

Thanks for all the help, guys. Cheers.

EDIT: Just out of curiosity, I found the price for a new driveshaft housing...$135 and no one has them. Too rich for my blood on this engine anyway.

 

[pvanv]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

It may have been stored in freezing weather and not stored vertically, and may have frozen/broken. If the block is OK, you can fix the rest; otherwise, it's time to part that one out.

 

[laurentide]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

It may have been stored in freezing weather and not stored vertically, and may have frozen/broken. If the block is OK, you can fix the rest; otherwise, it's time to part that one out.

Would you mind giving me a brief description of what would be involved in this fix? The block itself is fine. The damage is on the drive shaft housing right between the two forward bolts. Would a weld shop be able to fabricate a piece?

Thanks Paul.

I'll try to get a photo in the morning...I don't think a flash shot right now would show anything.

 

[laurentide]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

This is from the driveshaft housing diagram, and the red is the outline of the missing piece. To me it seems a bit complex to try to fix, but my knowledge is admittedly extremely limited on this subject:

EDIT: the inner walls of the exhaust and cooling conduits are intact, it's the outside part that's missing. So if you can imagine that red line on the side you can't see in the image (the front). A couple of photos will probably make a lot more sense.

Thanks.

 

[laurentide]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

I'm just now realizing that you probably mean replace the housing with a new one...I did find a site that has them in stock, but I'm going to wait until my boat resto is a little closer to being done to drop the cash on one if I go that route.

 

[pvanv]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

The Long housing is in stock; the short is out of stock right now. Either way, the cost will approach the value of the motor. YMMV.

 

[laurentide]

Re: Tohatsu M8B shifter cam...and I'm an idiot.

I have the long shaft. And yeah, I'm just going to keep my eye on the local CL while I decide whether or not to spring for it. Thanks again.