My Tohatsu help thread!

[Bus_Boy]

Hello everyone, i recently purcahsed a used 25/30 Tohatsu 2 stroke. I thought i would start a thread which i can ask multuiple questions in , rather than begining a new thread every time i have a new question regarding my motor. I will take some pictures tommorow and use a paint program to try and point out and explain as best as i can any problem areas.

The motor starts and appears to run fine, my first question is about the prop.

When i spin it slowly by hand, it seems as though something is bent somewhere. It's like if you were to spin a bicycle wheel that is buckled. There is a small gap between the prop and the leg, and the gap goes bigger and smaller when it spins. Any idea's? It also jiggles a little bit in the direction of where it's bolted on.

[Mattywooo]

Hi mate thanks for the reply on my recent post.

Sounds like the prop may have hit some hard ground or somthing and like you say slightly bent the drive.

Im not to great on outboards as only just started boating.

The prop has hit somthing i would say, im sure some more experienced members will help out..

Cheers.

[Bus_Boy]

I'm pretty sure it has taken a hit somewhere as there is a chunk out of the Skeg. If it's safe to run as it is, i'll probably leave it for the time being, but if it can cause serious issues, then i will address it asap..

[9D280]

If you got a lump out the skeg it sounds like it's hit something. Any lumps out the prop or one blade at a different angle to the rest?

What to do is tape a piece of wood or something to the leg, so it's really cliose to the tail end of the hub and canlt move, then turn it. If thre gap that open & closes is a lot bigger than the one at the gearbox end, you may have a bent shaft.

If it's not touching the gearbox at all, you might get away with it for a while but the imbalance will shake the grearbox to pieces eventually * gve yopu a rough noisy ride. (although going by your other paost that may not be an issue! )

[Hightower]

The first thing is to check if it's the Prop that's running out or the prop shaft.

Take the prop off and put to one side.

Get a knitting needle or a long pointer and some Plasticine/blue tack. Using the Plasticine/blue tack, stick the pointer on to the gearbox housing or somewhere that doesn't move. Then position the pointer on the end of the prop shaft (not the thread). You can then rotate the shaft and look for gaps between the pointer and shaft. If it's an even gap (doesn't get bigger and smaller) when you turn it then the problem is with the prop. If the gap gets bigger and smaller then the problem is with the shaft and it will probably need truing up or replacement.

Whatever's wrong I would get the oil checked in the gearbox as vibration is the death knell for seals and bearings and I wouldn't run it unless you were stuck somewhere for risk of further costly damage.

If it's going to cost you an arm and a leg for repair then any good insurance policy should cover you for underwater/leg damage.

Post back you results.

[Poly]

Originally Posted by Hightower

If it's going to cost you an arm and a leg for repair then any good insurance policy should cover you for underwater/leg damage.

Not if the damage was there when bought:

i recently purcahsed a used 25/30 Tohatsu 2 stroke

[Hightower]

Depends if you've used it yet. You'd have very little come back if you accepted after a Sea trial and would be looking for "good will" from the seller. If someone came back to me after buying a boat I knew was solid, moaning about a bent prop shaft then I'd tell em to take a hike.

Have you used it yet Bus Boy? Did you Sea Trial it before purchase?

[Bus_Boy]

No i haven't used it yet. I need to pick up some 1 way valves for my Zodiac after i missplaced the originals.

Due to my remote location, i bought the motor interstate, and then had it freighted to me. After patiently waiting for 4 months, i was unable to find anything in my area, so i had to look at other options.

I will take the prop off today and report back. I also have some photos i need to upload which show a bit of play in the lower section of the leg. There is a bit that moves up and down when you select F/N/R, and the round housing around it has quite a bit of movement, and makes a bit of a sloshing noise when you move the leg around. I'm hoping it's just a few worn bushes or something a not something serious....

Looks like a may have bought a bit of a dud motor which is unfortunate. All i can do i guess is hope that with the right tools and the right advice, i can fix anything that needs doing, and get the motor in reasonable shape without having to spend a whole lot of money on it.

[Hightower]

That looseness could be caused by an out of balance bent shaft buggering up the bearings then. Good luck with your tests, please report back your findings.

[Bus_Boy]

Ok so i got the lower section of the leg off today. I checked out the water pump, impellor which ever it is while i was there, and the gaskets on it were completely buggered, and there was a lot of crap built up around it aswell. So i'm going to need to replace that while the legs off.

When i spin the long shaft (the one that goes up to the motor) the prop shaft spins, but instead of just rotating, the outside point of it (where the nut goes on) it's moving around in quite a large circle, obviously indicating that something is bent somewhere.

What should i do? Take it to a mech, or is this something i could fix myself for less?

[Poly]

Originally Posted by Bus_Boy

Ok so i got the lower section of the leg off today. I checked out the water pump, impellor which ever it is while i was there, and the gaskets on it were completely buggered, and there was a lot of crap built up around it aswell. So i'm going to need to replace that while the legs off.

When i spin the long shaft (the one that goes up to the motor) the prop shaft spins, but instead of just rotating, the outside point of it (where the nut goes on) it's moving around in quite a large circle, obviously indicating that something is bent somewhere.

What should i do? Take it to a mech, or is this something i could fix myself for less?

There are some people on here who would tackle that as a DIY job, but I think the vast majority would not start dismantling the bits inside the lower leg themselves. I'd say unless you are really quite experienced it is NOT a DIY job. The bad news is i is also likely to be an expensive job - and it may be cheaper to replace the whole "lower unit" if you can find one somewhere.

[Bus_Boy]

Little bit lost on this one also. Sorry for the small image, i couldn't make it any bigger. There is a pink circle outlining the area i am raffering to.

I can see a few rubber bushes, which are perished. Also, should their be anything covering the shift linkage?

I've undone 4 bolts, 2 on either side, where these worn rubbers are, but i can't seem to get to them. How do you seperate the rest of the leg where it swivels left to right?

There is a lot of play in this area.

One a brighter note, i fixed the play in the tiller arm today. I couldn't get the bolts any tighter, so i removed them and added 2 extra rubber washers with a metal washer spacing them, replaced the original bolts with SS one's, and now it tightens up with no play at all, so i'm happy there..

[Bus_Boy]

As you can see in this image, there is quite a bit of damage to the skeg. This is an old image, since then i have dropped the unit off, and also sanded it back ready to re-paint once i've sorted the bent shaft issue.

I'm planning on just grinding the skeg following it's original shape as much as i can,(2nd image shows my proposed lines) but obviously i'm going to end up with a fair bit less metal than how it originally was. Is there anything to be carefull with when doing this, like when it's no longer solid and become hollow?

Is is ok that i will have a smaller skeg when i'm done with it? I plan on doing this tommorow when i can borrow an angle grinder.

Appreciate any advice before i begin, and will post results back tommorow.

[Bus_Boy]

Well i got the prop shaft odd today, and yep, it's definately bent allright, quite a bit too by the look of it. Against the advice of pulling bits of the g/box out myself, i figured it would be better to try, and if need be pay someone later to help me re-assemble, rather than pay them for the whole job. All though i took some pictures and did some drawings along the way, and i'm pretty confident about putting everything back together.

I think the skeg turnout out OK. I probably could have spent a bit of time getting it all perectly straight, and maybe even a bit sharper, but chances are sooner or later, it's just going to get whacked again. So for the time and effort spent, i think it's allright.

Looking at the pic of the shaft, does it look like it could be straightened out ok?

[Poly]

I've never had a bent prop shaft but suspect it will be impossible to get it perfectly straight again?

If you are expecting to "touch the bottom" in the future, then it might be better to get the skeg welded (a specialist job) so it is the right size again. Currently your prop will touch the ground before the seg (which normally bumps the engine "up" and so protects the prop from serious damage). You might find that you are damaging the prop and possibly your nice new prop shaft without that protection.

Something like this might save you having to get it welded: http://www.boatstoreusa.com/productd...?productid=980 or http://www.blackfinskeg.com/home/

[Bus_Boy]

Well the damage was caused by the previous owner. If the skeg is ok as it is now being about 3/4 shorter, then i will leave it as be....I'm fairly cautious and have never bent a shaft, or damaged a prop in the past myslef. Best if i can fix it myself without having to spend anything..

[Bus_Boy]

Can someone give me advice to remove the mid section of the leg? Does it just unbolt from under the cowling and then drop off?

[Bus_Boy]

Ok, good news, i took the shaft to a driveline store, and they were able to straighten it out for me for 50 bucks. I spoke to a marine shop, and apparently they send quite a few bent shafts to them for repairs.

The rest of the g/box seems allright, so i will put it all back together tommorow and see how it goes. 2 washers and a round coupling fell out in the dissmantle, and i'm not quite sure where they go in. If anyone can tell me that would great.

Bad new, the top and bottom mounts are completely persihed. I've got my hands on some solid mounts, but i can't figure out how to get to the old mounts. I've undone the bolts i can see, but nothing gives...

[9D280]

Leg mounts:

Bottom ones are likely to be bolted through the "hanger" at the bottom of your"rudder shaft". 2 nuts on the forward end. If not (i.e the shafts are integral to the hanger), then you'll need to remove the two covers on the side of the leg, where you will likely find a couple of screws holding the rubber A/V mount in place. Most engines are a variation on that theme. That's the easy one.

Top is likely going to involve removing the powerhead / lower tray to get access. The leg is wider there, and it's more visible, so the A/V mounts are usually bolted in from the inside.....


Also might be worth pricing up a new set before you start dismantling - when I did mine the replacements were going to cost more than I paid for the engine in the first place! (which is where you might be better bearing in mind the state of your gearbox finding an engine that has a seized powerhead & doing a swap of all the decent bits to one engine)

(PS anyone want a Merc/ Mariner clamshell leg? )

[Bus_Boy]

Well i priced the mounts today, $99 (aus) for a complete set of solid mounts, top and bottom, so not too bad. I took the powerhead out today, was a fair bit of a job on my own, but less complicated than i had originally thought.

Have been advised to replace prop seals, as the original oil was a little milky, indicating there was some water getting in.