Need info on Tohatsu M9.8A

[daveh77]

Greetings,
I just acquired what is evidently a "vintage?"
Tohatsu 9.8 2 stroke, Model M9.8A, Serial 23093
I have been searching without success for any info on that model.
All I find in manuals or parts listings are M9.8B.
Forum discussions all seem to be even newer C & D models.
Does anyone have any help or info on my old model? What year would it be?
Parts availability? OK or obsolete?
It has been sitting in a shed for years, boat nearby last registered in 2012.
Sadly the owner had a stroke and can't talk, wife doesn't know anything about it.
Cowling is faded from the sun but inside it looks like brand new except a thin line of blue gasket cement oozed from the head gasket, don't know if that is factory or not. Has 'decent' compression, but that is subjective. Suggestions for test run? What brand of gas hose connection is it?
I also got a 7.5 Gamefisher, same condition, same story. 217-585380, 8B-158634
THANKS! for any input.
Dave

 

[pvanv]

The B came out around 1998. In North America, that was followed by the 4-stroke motors. Yes, the A is quite obsolete. No water pump kits, and no carb kits, etc. Probably uses the Tohatsu 2-stroke fuel connector.

 

[daveh77]

Thanks Paul. I was hoping you would answer. So is it just a big anchor or worth the effort to work on?
I can probably trade it back for a 5.5 Evinrude, same story same condition, square not round housing, unknown year but needed 9.8HP more than 5.5. Thoughts?

 

[daveh77]

Looking at the carb, it looks more like a dirt bike carb than every other outboard carb I have seen. Everything on outboards look so foreign to me but this looks just like a small Mikuni or similar like off a Japanese 50 or 80 cc dirt bike. Is that my imagination? If so, not too worried about a carb kit.
Water pump kit is a bigger problem. Suggestions? Ebay? Or?
Is it too obsolete to have any value?
Junk it and move on? Or part it out?
Brand new to boats and outboards so please forgive the newbie questions.
Thanks, Dave

 

[Sea Rider]

Dissasemble the carb, clean jets, nozzle, micropolish the float valve seat. If all rubber parts are still in good working shape try to start the motor, assume the motor doesn't count with a fuel hose in which case will need to get any fuel hose with a primer bulb remove both connector ends, connect one side direct to the fuel pump, the other into a fuel container with pre mixed 50:1 fuel/oil ratio. With time and patience all carbs can be recuperated...



If the head gasket has a thin line of a blue material has been previously removed and put back in. Original head gaskets comes with a 2 side self sealing layers that seals once the motor has been put into operation.

Happy Boating

 

[km1125]

With all the impellers out there in the market, I'd be surprised if you couldn't find one that could be made to fit and work sufficiently.

 

[daveh77]

Sea Rider, I was also hoping you would show up. I have already learned a lot from posts by you and Paul. And others but you two seem to pop up most often.
Your carb advice is exactly what I was looking for, thanks!
KM, not my area of expertise but I was hoping you are right about replacement impeller options.
Thanks to all for help on this 9.8 Tohatsu.
Any more thoughts or suggestions are very welcome.
(I'll make a new thread on the air cooled Sears units.)

 

[Sea Rider]

Don't know if the 9.8B2 impeller is compatible with a 9.8A impeller, tried to find info to check that out but that model is quite obsolete and not listed nowhere as to compare both.

What's the current impeller condition ? If the vanes springs back near or horizontal when out of the liner it's still good to go, flip it and use the newer side. Micropolish the WP liner in circular motion with toothpaste till all the circular micro lines/scratches has been removed, the impeller will last longer along pumping the right amount of water specially if all water passages are clean...

Happy Boating

 

[Sharpie223]

I'm resurrecting this thread as I'm pretty sure that I am the new owner of the motor Dave had. Since this was the main thread of info I found at the time I purchased it, I figure it would be good to leave some info here.

Main thing with this motor was the water pump. The impeller was cracked through the bushing. I found that I could modify a yamaha 9.8 impeller by drilling the bore to 9/16", filing the keyway, and it worked. The part number was 682-44352-01. It's a mm or so larger in depth and diameter, but it bolted together. That said, to test, there is no way to attach ear muffs or a hose, so you have to submerge in a bucket, and it needs to be deep enough or the impeller won't generate enough pressure to give a good stream, this gave me some head scratching to figure out. I think it has to do with an overpressure prevention system. It was a bare trickle just submerging to the cavitation plate, a few inches more and it was a good stream.

Other than that, this motor was definitely used in salt as evidenced by the white corrosion on the aluminum parts. Also the drive shaft is two piece, coupled by a square drive. The coupling rusted together preventing me from getting the water pump and impeller off. So an angle grinder and repair section with square tube solved that.

Going to test top speed in my 14 footer tomorrow, staying in slack water in case I end up rowing.

 

[GA_Boater]

I'm pretty sure this thread is closed. Start a thread of your own and refer back to this thread.

Closed.