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Old 21-03-2015, 22:30   #1
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Tohatsu outboard 9.8 slips under load

I have a 2009 Tohatsu 9.8hp outboard. Under load the propeller seems to slip and allow the motor to free rev. If I back off the throttle the motor goes back to normal and I can move forward. Any suggestions as to the problem.
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Old 21-03-2015, 23:01   #2
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Re: Tohatsu outboard 9.8 slips under load

The rubber hub in your prop has spun. Get it fixed or get a new prop.
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Old 22-03-2015, 00:39   #3
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Re: Tohatsu outboard 9.8 slips under load

Thanks Reefmagnet, that's exactly what is happening. The prop is stil in god condition. Who might repair it or is it better to buy a new prop, worth about $60 I see on the net. Does the 8.5 stamp on the prop refer to the pitch or diameter. If it is the diameter then how do I tell the pitch? Appreciate the help.
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Old 22-03-2015, 01:04   #4
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Re: Tohatsu outboard 9.8 slips under load

Cheers - have one of these donks myself. My wife calls it "her baby" lol although I prefer our Yammy 5 for portability. I'd buy a new prop - they're cheap enough. The number is the pitch and you should find they are available in 2 or 3 pitch options.
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Old 22-03-2015, 01:34   #5
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Re: Tohatsu outboard 9.8 slips under load

Outboard props have a rubber bush that is sort of like a safety valve. If you hit an object with the prop, the bush breaks rather than the prop or the gearbox. I think on your motor it is referred to as a propeller thrust holder. All you need to do is remove the prop, remove the thrust holder, get a new one and reinstall. All should work okay then. Simple thing to do yourself.
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Old 22-03-2015, 09:15   #6
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Re: Tohatsu outboard 9.8 slips under load

Hi
your propeller has a rubber holding to the shaft that is broken (not really but its slips).
Take the propeller out of the shaft, you will see how is making the connection between the propeller and the shaft.
You have 2 ways to repair it:
1. To bay a new propeller...the best solution.
2. To make the holes diameter 3mm or 4 mm, at 120 degrees 3 holes, in the metal part when you watch from the front and with special instrument make the treads M3or M4.
Then do the montage propeller on the shaft, and tight the special bolt
with hexagonal head, to hold the propeller to the shaft without slipping.
This solution is temporary, because the bolt that you tight can broke also...

Vasco
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Old 22-03-2015, 16:33   #7
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Re: Tohatsu outboard 9.8 slips under load

What I find really frustrating is that a pop-up advertisement on this site covers up the message I'm trying to read and there is no means to make it go away!

GRRRRRRRRRR!
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Old 22-03-2015, 16:39   #8
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Re: Tohatsu outboard 9.8 slips under load

Quote:
Originally Posted by vasco6088 View Post
Hi
your propeller has a rubber holding to the shaft that is broken (not really but its slips).
Take the propeller out of the shaft, you will see how is making the connection between the propeller and the shaft.
You have 2 ways to repair it:
1. To bay a new propeller...the best solution.
2. To make the holes diameter 3mm or 4 mm, at 120 degrees 3 holes, in the metal part when you watch from the front and with special instrument make the treads M3or M4.
Then do the montage propeller on the shaft, and tight the special bolt
with hexagonal head, to hold the propeller to the shaft without slipping.
This solution is temporary, because the bolt that you tight can broke also...

Vasco
Please don't do this! The rubber is there to protect the engine and powertrain should you inadvertantly hit something.
Do get the prop repaired (rubber replaced) or buy a new prop, repair the old and keep as a spare just in case.
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Old 22-03-2015, 16:55   #9
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Re: Tohatsu outboard 9.8 slips under load

There is not agreement on rehubbing a spun prop. As others have noted the drive shaft and the rubber hub have a bad connection. It is possible to replace the rubber hub, you basically remove the old one, clean out the bits of rubber, use a some what special lube and force a new rubber hub in the prob. Some prop shops will do this, others will not. Some shops will suggest OEM parts to rehub. While the disagreement is not as big as that about anchors or guns on boats you will find some folks with very strong opinions on rehubbing verses buying a new prob.

My advice is to buy a new prop and install it and get the old prop rehubbed and keep it as a spare.
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Old 22-03-2015, 17:00   #10
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Re: Tohatsu outboard 9.8 slips under load

Buy a new prop for 50 bucks, and if you're cruising buy two!


Toronto in summer, Bahamas in winter.
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