TOHATSU 18HP E2 TYPE, 2 STROKE ENGINE

[ak5609]

When we recently bought our sail boat, it came with a tohatsu 18hp e2. Two stroke.

Worked fine for 3 month, but now the gear/ transmission is slipping.

I have no idea how to describe the problem, but maybe sailors do know.

Something is worn out in the geasr box.

I now hope somebody has a good idea how i get to know this outboard engine to take it apart and also service it in the future. An interesting link would be great way to start.

Maybe somebody has the same engine and is willing to send some instructions.

Thanks in advance and kind regards

Alex

[44'cruisingcat]

Sure it's not the propeller hub slipping? Outboard props have rubber bushes in the hubs, to protect the gearbox if you hit rocks etc. It's not uncommon for the bush to start to slip in the hub.


A slipping gearbox is pretty hard to imagine. They're either in gear or not. There would be severe crunching/grinding noise if it wasn't in gear properly.


A slipping propeller hub will give the sensation of engine revs increasing, while the boat goes slower.


Getting a prop re-bushed isn't usually expensive. Or if you can find someone with a similar motor, (I think Mercury 15's would have the same prop spline) and borrow a prop to see if it fixed the problem?

[ak5609]

WONDERFUL NEWS.
DO YOU HAVE A LINK FOR US HOW TO CHECK AND FIX IT?
THANK YOU SO MUCH.
ALEX

[ak5609]

WONDERFUL NEWS.
DO YOU HAVE A LINK FOR US HOW TO CHECK AND FIX IT?
THANK YOU SO MUCH.
ALEX
Edit/Delete Message

[Kayoko Monk 33]

Tohatsu and Nissan same thing, try ebay for a spare prop, plenty to chose from, less than a hundred bucks

[Terra Nova]

Those prop hubs can be replaced IIRC.

[ak5609]

Originally Posted by 44'cruisingcat

Sure it's not the propeller hub slipping? Outboard props have rubber bushes in the hubs, to protect the gearbox if you hit rocks etc. It's not uncommon for the bush to start to slip in the hub.


A slipping gearbox is pretty hard to imagine. They're either in gear or not. There would be severe crunching/grinding noise if it wasn't in gear properly.


A slipping propeller hub will give the sensation of engine revs increasing, while the boat goes slower.


Getting a prop re-bushed isn't usually expensive. Or if you can find someone with a similar motor, (I think Mercury 15's would have the same prop spline) and borrow a prop to see if it fixed the problem?

WE FOLLOWED YOUR ADVICE YESTERDAY, BUT FOUND NO WEAR-OUT INSIDE THE PROP BEARING.
BUT MAYBE YOU CAN HELP ON FOLLOWING INFOS: WHEN WE PUT THE MOTOR IN REVERSE OR FORWARD GEAR (OFFCOURSE NOT RUNNING) AND TURN THE PROP COUNTERCLOCKWISE THERE IS COMPRESSION. CLOCKWISE THERE IS NONE. WE CAN TURN THE PROP EASILY AND IT MAKES A CLICK SOUND 20CM ABOVE THE PROP, MAYBE IN THE GEARBOX. EVERYTIME WE TURN IT . JUST A SHORT CLICK.

[44'cruisingcat]

That's normal. In forward the prop can "freewheel" when turning clockwise, viewed from the rear. I don't think it should freewheel in reverse though.


Did you try reverse? If you can turn the prop easily by hand in reverse, there may be a problem with your gearbox.

You probably won't be able to see a spun hub just by inspecting the prop. Best if you can try another prop on the motor.

[Reefmagnet]

+1 on the prop hub. The gearboxes use a spring loaded dog clutch to engage drive. Very unlikely to slip without making horrible noises. To test the prop, accelerate slowly which should be fine at least at low speed. Give the motor a burst of throttle and it will over rev without any horrible noises being emitted. If it is the prop, at that size, just buy a cheap non oem replacement. It's also a good opportunity to get another pitch if the original wasn't quite right.

Sent from my SGP521 using Cruisers Sailing Forum mobile app

[ak5609]

Originally Posted by Terra Nova

Those prop hubs can be replaced IIRC.

IIRC? WHATS THAT?

[ak5609]

Originally Posted by 44'cruisingcat

That's normal. In forward the prop can "freewheel" when turning clockwise, viewed from the rear. I don't think it should freewheel in reverse though.


Did you try reverse? If you can turn the prop easily by hand in reverse, there may be a problem with your gearbox.

You probably won't be able to see a spun hub just by inspecting the prop. Best if you can try another prop on the motor.

NO GRINDING. NO BAD SOUNDS. ENGINE RUNS SMOOTH LIKE A BABY. JUST SLIPPING GOIND FORWARD ACCELERATING.
THE PROP HUB LOOKS GREAT TO US.
I CANNOT IMAGINE THE PROP IS THE PROB.
WE TRIED REVERSE. SOUNDED GOOD AS USUAL, BUT OFFCOURSE WE COULDNT ACCELERATE AND TEST THE STRENGTH OF THE ENGINE.

[DotDun]

Originally Posted by ak5609

IIRC? WHATS THAT?

IIRC = if I remember correctly

[Reefmagnet]

Originally Posted by ak5609

NO GRINDING. NO BAD SOUNDS. ENGINE RUNS SMOOTH LIKE A BABY. JUST SLIPPING GOIND FORWARD ACCELERATING.
THE PROP HUB LOOKS GREAT TO US.
I CANNOT IMAGINE THE PROP IS THE PROB.
WE TRIED REVERSE. SOUNDED GOOD AS USUAL, BUT OFFCOURSE WE COULDNT ACCELERATE AND TEST THE STRENGTH OF THE ENGINE.

TYPING IN ALL CAPS = YELLING!

Now that's out of the way, it's the prop. Believe it.

Sent from my SGP521 using Cruisers Sailing Forum mobile app

[a64pilot]

99% sure the rubber hub in the prop is slipping.
While not the approved fix, I have drilled a hole in the hub and screwed in a sheet metal screw in.

1% chance you have a plastic bag on the prop or the mounting height / tilt so off it's ventilating the prop.
I'd say essentially 0% chance your gearbox is slipping.

[a64pilot]

Watch this, you have a pressed in hub, takes a machine shop to replace it.

https://www.youtube.com/watch?v=sNC4y0s2gwk