Logo
FULL SITE MENU

Tohatsu 50hp Won't Rev

N

Nollaig

New member
Hi,
I have a Tohatsu 50 hp, two stroke. It starts fine in the water; and runs very well. Then I stop and fish for a while. When I try to start her up again, it starts fine but has no revs. So, if you try to engage the throttle, the engine cuts out. Instead, I inch the throttle very, very slowly and eventually the revs pick up (say after a few minutes) and I head home with the engine in fine form.

I can't solve the problem; the mechanic said the engine is fine and the carbs have been cleaned. The fuel lines are fine and the battery is new. One mechanic said the problem is electronic, such as the rectifier, coils or CDI unit. But another mechanic said the problem is mechanical such as a head gasket slightly worn which is letting in moisture.

Any suggestions would be most helpful before we start more work on it.

Nollaig.
 
pvanv said:
What is the actual model/serial?
What is the compression?
Click to expand...

Paul

It is a Tohatsu 50 HP, two stroke direct fuel injection.
Model: M50D2 3E3

I have not yet tested the compression; it was serviced last year and the engine was running fine. The problem is after running it for a while, it won't accellerate after stopping. I was just wondering if anyone else had this problem.

I will bring it to the mechanic and have the compression tested for each cyclinder.

Nollaig.
 
I don't know what "carbs" were cleaned, but you have a TLDI, and definitely want a certified mechanic working on it.
 
pvanv said:
I don't know what "carbs" were cleaned, but you have a TLDI, and definitely want a certified mechanic working on it.
Click to expand...

Paul

Thanks for this. The carbs are fine. A very good outboard mechanic worked on it and it was only after it was serviced and back in the water that we noticed the problem. The mechanic now thinks that it might be the head gasket, but I have to bring it back to him now for checking. I was just wondering if anyone else had this problem and could advise me first.

I should have pointed out too that the outboard sat in a boatyard for a number of years without any use; so it might have got damaged from just sitting.

Nollaig
 
OK, M50D, not MD50. Not a TLDI. it's a 3-cylinder oil-mixing model. Very reliable. Definitely check over the whole fuel and oil system, and get new plugs in. If you have a thermal electric issue, the problem will only happen hot. Beware any minor o-ring leaks that allow the motor to draw air. Also verify clean and fresh fuel.
 
Paul

Thanks for this; I have had the problem for the last two years; I am in the West of Ireland so not easy getting it fixed (all diesel over here).

The fuel is clean and new plugs. It is just a nagging problem and capable of being worked around; just wait a minute or two or three and work up the throttle. Then she runs well. And yes, they are reliable; tohatsu engines.

The boat and engine sat for a number of years idle in a boatyard, and may well have got a leak there.

I will bring it back to the mechanic; he wants to check compression and plugs. He did mention before that it could be a problem with the oil.

Nollaig


pvanv said:
OK, M50D, not MD50. Not a TLDI. it's a 3-cylinder oil-mixing model. Very reliable. Definitely check over the whole fuel and oil system, and get new plugs in. If you have a thermal electric issue, the problem will only happen hot. Beware any minor o-ring leaks that allow the motor to draw air. Also verify clean and fresh fuel.
Click to expand...
 
biggie said:
I have a tohatsu 50hp too and iv got exactly the same problem did you manage to fix it in the end?
Click to expand...

Hi,

Strangely I have not yet put the boat in the water to run it; so I have not fixed it. I have not had the time, but hope to do it next week. I want to test it again and see if it still has the same problem. I suspect so, since it has been like that for three years now.

I checked with a few mechanics here; some say it could be the ignition coils (there is one for every plug so there) or the rectifier but the importer for Tohatsu in Ireland said it more likely the CDI. They say it is unlikely to the ignition coils or the rectifier. I need to take it to them for testing; but they are three hours drive away in Kerry. So I would prefer to test it again locally. I don't fancy the long tow.

A new CDI unit costs about 300 bucks (or euros), so I need to be sure that that is the problem. It is not a major issue; I can wait for a couple of minutes and the engine recovers. It is a nuisance though. I hope to sort it out eventually....

I hope to have the boat in the water again next week, and will email you with the results. I don't think it is a fuel problem or the spark plugs; it is more than likely electronic. A good mechanic should be able to test it; but I am based in the West of Ireland and most boats here operate on diesel.

Let me know too if you can trace the problem; you might be able to source a better mechanic there.

Nollaig.
 
Back
Top