Tohatsu M8B - Should I buy it?

[leonidas]

I am looking into buying a used Tohatsu M8B - extra long shaft, 2 cycle, about 10 years old. This will be a spare engine for my inboard/outboard Mercruiser 170 HP ski boat. There is an adjustable mounting plate on the transcom. I measured from the top of the mounting plate to the bottom of the transcom and it appears that only an extra long shaft should work.

I would like to know if there any issues with these engines that I should be aware of. The engine was used in a sailboat and I assume that it was in salt water. From the picture it appears to be in great condition. Do these engines have any weaknesses? ANy input would be appreciated! I am new to this forum.

Leon

 

[TOHATSU GURU]

Re: Tohatsu M8B - Should I buy it?

Ten years old and a saltwater sailor owned it...That usually means zero care. I would probably pass on it....But, I would pass on any ten year old outboard that was used on a blow boat

 

[leonidas]

Re: Tohatsu M8B - Should I buy it?

Are there any specific obvious items that I should be checking besides visible rust?

 

[TOHATSU GURU]

Re: Tohatsu M8B - Should I buy it?

Compression, gear oil, spark and then test run it.

 

[leonidas]

Re: Tohatsu M8B - Should I buy it?

Thanks. I am assuming that I need to pull the spark plus out and insert the pressure gage at each cylinder (one at a time) while pulling the cord. What are acceptable pressure readings?

In regards to the gear oil, I assume that I will pull the fill plug and look for evidence of water in the oil.

Finally, if the engine starts and runs OK, isn't this sufficient evindence that there is spark? Or should I do a separate test?

Sorry for these basic questions - I have a lot of experience with automobile engines but I am just getting started with marine engines.

Thanks again!

 

[TOHATSU GURU]

Re: Tohatsu M8B - Should I buy it?

1)You want them to be even. Don't worry about the number.

2)Yes

3)Mostly yes...But, look at the spark anyway. Your looking for them both to be big and bright. You can have good spark on on and weak on the other and have an engine that will run. My favorite thing to do during a test run is to pull the spark terminals off one at a time and see if the engine drops RPM. I especially like to watch other people do it with their fingers. But I am evil by nature

 

[leonidas]

Re: Tohatsu M8B - Should I buy it?

Great! Thanks for all the advice!

To check the spark (other than pulling one spark cable at a time while the engine is running) do you recommed a special tool to check it with (such as that found in automotive stores)? Or do you simply pull both spark plugs, and pull the cord while grounding each loose spark plug while connected to the spark plug wire?

Also, since you are in the business, are parts easily available? Are there any parts no longer available? I was told that this engine is exactly the same as the Nissan but some others seem not to agree.

Thanks Again!

 

[TOHATSU GURU]

Re: Tohatsu M8B - Should I buy it?

1) No

2) Yes

3) Yes

4) Everything is available.

5) Same as a Nissan