Tohatsu outboard engine problems 2

I have gotten my engine back from the service center on Friday and used it this weekend. I am starting to be rather disappointed in this engine. ( the Tohatsu MFS6BUL 4 STROKE 1 CYLINDER ) The service center told me that it is fine. That they couldn’t find anything wrong with it but they also said they didn’t even put it on a tachometer to check what kind of rpm’s it was turning in the tank. They also told me that as a one cylinder engine that it will vibrate. On the other hand they also told me the other day that they had never seen much less worked on one of these smaller engines. I honestly don’t have any idea at this point whether this engine is running the way it should be. (Note: the seller never did call me back or follow up in any way to my phone call and subsequent email to them..)

I also spoke with the people at Tohatsu again and have agreed to try the 7.9 inch in diameter 6 pitch power prop on the engine to see how that affects performance. This boat is in the range they recommend that prop for. I am willing to try it.. $54 or there abouts.

I have ordered a combined tachometer/hour meter that runs by induction off the engine spark plug wire that should be here this week. to test if the engine is running in its correct rpm range from [url][/url] roughly $40 for model 806-100-0222 Surface Mount “H”Hour Meter records up to 9,999.9 Hrs. in 0.1 Hrs. increments. Tachometer records up to 8,000 rpm with 1:1 (spark:rpm) firing pattern, or 4,000 rpm with 2:1 (spark:rpm) firing pattern. with a Resolution of 10 rpm. They told me with this engine it should read 1:1 on the phone when I spoke with them.

My impressions after running it in normal service conditions with extended periods at full throttle are….

1. It cranks easily and doesn’t die at the lowest idle
2. It is very economical on fuel. Where my old engine would use about 2.5 gallons of fuel to run the 5 miles out and 5 miles back on the waterway at full throttle this engine sees to be using about 1 to 1.5 gallons for the same distance. I will fill the the tank to a known mark on the tank and then next time I use it refill it to same mark to get an accurate mpg at full throttle.
3. the extended 25″ shaft is very nice. in wakes that used to pull the old engines prop out of the water, this engine doesn’t even come close to coming out.
4. After now putting it on the boat 3 times and having taken it off twice I like the light weight (55lbs according to tohatsu-though i haven’t actually weighed it myself) It is not hard to muscle it on and off the boat by myself.

1. though a few (very few) decibels quieter than my old 2 stroke it is still loud enough that it is painful to listen to before long at full throttle. it is very quiet at an idle and not bad at half throttle. I’m not sure but it seems to be louder now than when I first started running during the break-in period. It might just be that I hadn’t run it at full throttle much at one time prior to this weekend.
3. The vibration is much worse than the 2 stroke engine. with the tension adjustment on the steering as tight as it will go the engine will gradually vibrate/move till it is trying to turn the boat to starboard. eventually the tiller handle will hit the port side of the transom cutout. At an idle it will do this in a few seconds. At speed the vibration smooths out enough that it takes a little while.. this isn’t to say that the vibration becomes less just that it is a higher frequency at full throttle.
4. The vibration is such that i fear it will be a regular item of maintenance to check all nuts and bolts on the engine after a while to make sure they haven’t started to work lose and also all bolts on the transom of the boat such as the motor mount bolts and all bolts holding the gudgeon’s on .
5. At full throttle the boat is now running about 5.4 to 5.5 knots. Still slightly below the thrust provided by the old 4 hp 2 stroke.

This is my review of this product ( 6hp MFS6BUL 4 STROKE 1 CYLINDER ) to this time.. I will continue to post on it as I get more information.

The prior posts on this are

5/24/07 what a waste… sigh.. i called the local service center that I had asked last week to order the 6 pitch prop and they didn’t even order it. So far the only decent treatment I have gotten out of this situation is Vic at Tohatsu and the service guy I spoke with at who didn’t even sell me the engine.

4 comments to Tohatsu outboard engine problems 2

  • Damn shame… I’ve just gotten a 3.5 HP four-stroke Tohatsu, based on the experiences a friend had with hers. Haven’t had a chance to use it yet. Like the Sendec units…have one for the Honda OB on my trimaran, and will be getting one for the little Tohatsu.

  • Yeah
    I just exchanged messages on the website forum with another guy that got one the week before I did and he is happy with it. However he says in 2 ft of chop his is pushing him at 6 knots with the same prop I’m using now. Mine totally doesn’t reflect that performance. I totally don’t know what to think about my engine.

  • Lee

    What service center have you taken the motor to? I had mine serviced by Sammy’s in Lorris. He eventually got the problem diagnosed and fixed.

  • I took to it to Sammy.. he says it is running fine as far as he can tell but he also admitted he had never even seen one of the small outboards like mine.. I guess he is used to working on bigger ones. I just got back home from a sailing this weekend and the sendec unit is in. I will install it this week and run some tests.

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