tohatsu 9.8 corrosion on vertical shaft

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xort

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I have the Tohatsu 9.8 2 stroke outboard.
The steering has become extremely stiff and there is corrosion/rust on the vertical shaft from the power head to the lower unit.
I tried greasing the zerks and that did not help.

Will replacing that vertical shaft fix the problem?
How difficult is it to do that replacement? We cruise full time and don't have a workshop with specialized tools to do major repairs but I have done plenty of minor stuff on the back deck of the boat.

Thanks
 

Sea Rider

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Is the engine used in fresh or salt water ? You want to remove the shaft located inside the swivel bracket, right ? If so, will need to remove lower mounting bracket to disconnect engine body from swivel bracket. Once engine is off pull shaft upwards. Probably will need to squirt some W-40 to loosen shaft.

My 2006 engine which was evenly washed after each use developed same. Just filed down all shaft corrotion with sanding paper, took advantage to change both steering bushing located on shaft, had excesive side play from constasnt use.

Light coat shaft with grease, once is fully in and engine mounted back on mounting bracket, with a grease gun fill the entire SB with waterproof grease untill grease exists through upper and lower bushings, that way will lessen water intrussion there. A re grease is a must do from time to time to avoid or lessen shaft corrrotion. That part should be expenensive, try to fully recover your current one.

Happy Boating
 

pvanv

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Is the steering friction adjustment correct? If so, pull the steering shaft system apart as Luis recommends, clean and re-grease. In future, regular greasing will help prevent corrosion on the swivel shaft.
 

xort

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Salt water

its the shaft that turning it pivots on and the shifter linkage is inside this shaft.

is yours a 4 stroke? different than the 2 stroke?
 

xort

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paul
steering friction bolt is backed all the way out. tried greasing and that made very little difference. is there much complexity to the shifter linkage being inside this?
Cursory glance, it looks complex!
 

Sea Rider

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Mine is a 2 stroke 18 HP. To fully access and remove steering shaft will need to pull complete powerhead off pan, then remove shift rod lever to free upper shift rod, must also remove upper pin from brass coupler located on lower leg to pull rod fully out from inside shaft, then can procede to remove both lower mounting brackets and pull engine body out.

There's no possible form to remove steering shaft without removing shift rod fully out. Same work done on my engine was a straight forward job due to having block completely removed from pan, lower leg included as both were undegoing full preventive maintenance.

Will need to buy a new lower gasket as usually comes out damaged when removing block out pan. Old gaskets were cardbord type, have been replaced with new metalic ones, at least on the 15-18 models is so.

Happy Boating
 

pvanv

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1. The shifter is not inside the steering swivel shaft, it is forward of the actual shaft.
2. You do not need to (but you can) remove the power head to expose the steering shaft bushings, but you will be separating the lower motor mount brackets to disengage from the tilt/swivel bracket. In order to get clearances, you will need to disengage the shift coupler and drop the LU, and then the entire upper section can be pulled free from the swivel bracket, exposing the steering shaft.

You can then clean the old hardened grease from the shaft and bushings, and sand-paper any corrosion from the shaft. Then re-grease, reassemble, and finally pump some grease into the zerks. If you over-grease, you may reduce the ability of the steering friction bolt to tame the steering.

002-21030-5_FIG12.JPG
 

Sea Rider

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Paul,

What if he pulls carb off, will he have enough clearance to work freeing the upper shift rod out once has disconnected lower shift rod from coupler ? If the lower shift rod is seen popping through middle lower steering shaft definitely goes through the entire whole shaft. Same part scheme as of the 18 HP.

Happy Boating
 
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xort

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just fixed my notifications, wasnt getting any.

Paul
I did see that the shifter is outside this shaft but there is another rod inside that looks to go all the way from top to bottom.

Ultimately here is my issue. I'll be living on the boat on a mooring for the next 2 months and need the dink to get ashore with the engine. I dont want to get in over my head and have to row!!

Can I hang the engine on its mounts on the inside of my stern rail to do the repair on the back deck of my boat?

I have a fairly complete set of standard tools. Will I need anything special?

Dropping the Lower Unit sounds serious, never done that. Complicated?

Where can I get a service repair manual for this engine? Here on i-boats?

Thanks
 

xort

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Forget that last question...just ordered the service manual

Doesnt sound like I'll need any parts??
 
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Sea Rider

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Xort,

The shift lever has nothing to do with shift rod although is attached to it. If you don't have enough clearance after pulling carb out will neeed to remove power head off to have cleartance to work removing upper rod from shifter. You can leave swivel bracket mounted to rail once main body is pulled out, just don't drop any small part into the blue.

If you remove power head no need to drop LU, just remove upper spring pin with tool and pull shift rod upwards from pan. Will pass straight through shaft.

Happy Boating
 
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pvanv

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Paul,

What if he pulls carb off, will he have enough clearance to work freeing the upper shift rod out once has disconnected lower shift rod from coupler ? If the lower shift rod is seen popping through middle lower steering shaft definitely goes through the entire whole shaft. Same part scheme as of the 18 HP.

Happy Boating
Completely different setup. Can leave the shift rod in place; just disconnect at the coupler.
 

pvanv

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just fixed my notifications, wasnt getting any.

Paul
I did see that the shifter is outside this shaft but there is another rod inside that looks to go all the way from top to bottom.

Ultimately here is my issue. I'll be living on the boat on a mooring for the next 2 months and need the dink to get ashore with the engine. I dont want to get in over my head and have to row!!

Can I hang the engine on its mounts on the inside of my stern rail to do the repair on the back deck of my boat?

I have a fairly complete set of standard tools. Will I need anything special?

Dropping the Lower Unit sounds serious, never done that. Complicated?

Where can I get a service repair manual for this engine? Here on i-boats?

Thanks


In the field, it's considerably simpler and easier to drop the LU and release the lower mount than it is to pull the power head, lower cowl, upper mounts, exhaust housing, etc... In the shop, we might go at it from the top, but we have good gasket scrapers, lots of sundry spare parts, etc., which are required when pulling the power head.

Once the LU is off (4 bolts and the shift rod coupler)(the drive shaft will come down with the LU, but the water pipe will stay with the upper section), then after releasing the lower motor mount (and any associated ground wires, etc.), you can flex the upper mounts, and pull the entire motor off of the bracket, complete with tiller handle, exhaust housing, steering shaft, etc... leaving the steering shaft bracket and transom clamps behind. Since the steering shaft is recalcitrant, it will likely take some patience and wiggling, and maybe some levering.

While you have the LU down, if the water pump hasn't been serviced in a few years, it would be a good time to install a new WP kit (not just the impeller).

It would be a lot easier to work on a motor stand ashore, but in a pinch, you could use a kicker pad to hold the bracket. Beware dropping parts or tools overboard. You will need standard metric tools, especially a 10 mm box wrench for the LU bolts, and a decent set of 3/8-drive metric sockets. You will also need a punch to drive out the 3 mm ss roll pin that connects the brass shifter connector to the shift and cam rods. If you motor ashore in the morning, you should be able to complete repairs during the day, and then motor back to the boat for a celebratory supper aboard.

I recommend that you get a Factory service manual, as opposed to the way-too-general aftermarket manuals that are available from non-Tohatsu dealers on the Internet, but, since you already have one on order, see if it helps. Study the setup for a while, have tools on hand, and toss your fears aside. It will take a novice a lot longer than an experienced technician, but it isn't rocket science. One benefit of being ashore is that if you get stuck, you may be able to get help from someone else ashore; If you are isolated on the mooring, help will be harder to come by.
 

xort

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Paul
When pulling the LU, will I spill the LU gear oil? Sounds like no, since the shaft comes down with the LU.

Sounds like I'll end up with 3 parts...the LU, the power head and the transom bracket. Then remove/repair the tube.

Thanks much Paul!!
 

pvanv

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The LU lube will be contained inside the seals of the LU, so no spillage.
Yes, you will have 3 major components.
 

xort

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Looking closer at the tube...its flaking large chunks of rust. Need a new tube. What is a good source of tohatsu 2 stroke parts?
 

pvanv

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The job just got more involved, as you will be completely removing the shaft assembly. Probably need to count on at least a full day for a novice mechanic to complete everything.

You can get genuine parts from any dealer... several forum members are dealers... even me.

Assuming your model is M9.8B, the part is:
3B2Q620100STEERING SHAFT$162.17
 
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xort

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Yikes! $162! For a tube?

how is this more complex than before?
Seems like remove tube and clean vs remove tube and replace.
 

pvanv

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I was originally suggesting cleaning the shaft while it was still attached to the upper section, but slid out from the bracket. If you must replace it, then you will be taking more stuff apart. The tube is a big part, including the "handle" at the front, the mount for the tiller, the upper motor mounts, etc. It is also hardened for strength, since it carries the entire thrust of the motor.
 
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