Tohatsu M8B

Don321

Cadet
Joined
Aug 4, 2010
Messages
7
I bought a used 8hp Tohatsu about 3 months ago it was running fine but all of the sudden I can't start it is almost impossible to pull the starting rope I pulled the spark plugs and sprayed solvent in it, it helped a little but still very hard to pull, any advise?

Thanks
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Tohatsu M8B

You will get more help in the Tohatsu section.
How does it pull with the plugs out?The recoil may be dragging somehow.
With the plugs out you should be able turn the flywheel withn your hands.
Did you mix oil in trhe gas at 50:1?
Sometimes a drive shaft will seize between the power head and the foot(gearcase)If you remove the gearcase on most motors it seperates from the power head and you can test the drive shaft and motor to see if one is the problem.
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,559
Re: Tohatsu M8B

If you forgot to add TCW-3 oil to the gas at 50:1 ratio (1 pint per 6 gals), you may have damaged the rings and cylinders, as well as the bearings.

If there isn't any lube in the LU, you could have bad gears and bearings there.

If it ran without cooling water circulating, you may have overheated the powerhead and warped/seized it.
 

Wee Hooker

Chief Petty Officer
Joined
Sep 11, 2005
Messages
618
Re: Tohatsu M8B

To add to what the others have said. If you didn't mix 50;1, your in deep Do-do and IMHO, the repair may cost more than the motor s worth.

Assuming you fed it correctly, then it could be something much simpler and cheaper to resolve.

First, when you attempt to pull start, is the motor in neutral and can you turn the prop freely by hand? If "yes", your problem is up top and quite likely in the cylinder or crank . (a compression check would be the next step.)
If "no", then your problem may be in the lower unit and/or the motor is out of adjustment for gear engagement. The next step here would be to drop teh leg as previously suggested.
 

Don321

Cadet
Joined
Aug 4, 2010
Messages
7
Re: Tohatsu M8B

Great,

I know the oil to gas mix was ok, I'm not sure about the water cooling because my son used last but he says it was ok, will try your advice.
Thanks.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Re: Tohatsu M8B

Great, my son used last but he says it was ok ?? :rolleyes:

Just going extreme: If your son has flipped at sea with engine on while boating, dropped engine to sea bed while installing/removing to/from transom, has not said a word about it, has rinsed engine head and cowling with tab water as nothing has happened, you have a KO engine, all interior bearings are almost seized.

Happy Boating
 
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