15 HP Tohatsu Water Cooling Problem

[victorjohn]

I have a fairly new 2002 15HP Tohatsu. Still breaking it in with less than 10 hours on the motor. After taking it out over the weekend, I noticed the water discharge opening was just dribbling water instead of the hardy pee stream I'm used to seeing. I'm planning to take it into the dealer for inspection, but it's a real hassle to do it. The dealer mentioned that it might just be debris in the system. I thought of this too, but thought that surely the screens on the water intake would keep debris out. Is there an easy way to check for debris and/or clear it in the line without having to rip the motor apart? I'd rather try to fix this myself instead going through the headache and logistics of hauling the thing to the dealer. I keep the boat/motor at our cabin which is about 105 miles away. If anybody has a suggestion, I would like to hear it.<br /><br />Thanks,

 

[TOHATSU GURU]

Re: 15 HP Tohatsu Water Cooling Problem

I doubt if anything is wrong other than the pee tube being clogged. Run it by a gas station and blow some compressed air back through the tube. Or when you have the engine out in the water ram a slim piece of wire up the tube while its running.

 

[victorjohn]

Re: 15 HP Tohatsu Water Cooling Problem

Thank you Elvin. I'll give it a try.<br /><br />Victor

 

[victorjohn]

Re: 15 HP Tohatsu Water Cooling Problem

You were right Elvin. I blew some high pressured air through the pee tube and problem solved. Thanks for the help.<br /><br />Victor

 

[TANSTAF1]

Re: 15 HP Tohatsu Water Cooling Problem

I have a 2004 9.8hp Tohatsu four stroke. Until last year I had the dealer winterize and store it for me but each year when I started it up for the summer the water would not come out of the colling exhaust port, so I would blow compressed air in the tube and this would fix the problem. this past winter I decided not to spend the $200 to "winterize" and store it. I simply flushed it with fresh water with a garden hose and "ear" muffs.

I have the same problem and tried the same solution. I got one spurt of water out the exhaust and then nothing.

Tohatsu on line FAQ's indicate the problem could be the impeller and in any case the impeller should be checked annually, but neither the online FAQ's nor the manual provide not directions or guide as to how to do this check of the impeller that they recommend. The manual says to have the dealer check the water pump and to replace the impeller every 12 months.

I called the dealer who sold me the engine and who has "winterized" it for the past few years, but they could not or would not tell me how to do it. The closest other dealers are 30 miles away.

Does anyone know how to check/replace the impeller. On a scale of 1 to 10, how difficult is it to replace?

 

[TGuy]

Re: 15 HP Tohatsu Water Cooling Problem

If you've never done it before and trying to do it without a service manual, I'd rate it a 9.532. If you have a service manual which shows exactly how to do it, rate it a 3.126. Unless you've used your motor in salt water and never rinsed it...then loosening the salt caked/corroded parts jumps it back to 10+ due to the frustration factor

bottom line, get a service manual and you should be able to handle it. You can buy service manuals and water pump kits from the Tohatsu Guru at internetoutboards.com

 

[TANSTAF1]

Re: 15 HP Tohatsu Water Cooling Problem

Hey thanks for the heads up! Can you also provide the formula used to provide such a precise difficulty level. Why does it get more difficult when you have the manual?

Anyway I flushed it with fresh water last year. Hopefully the Tohatsu dealer did also for the prior years as I paid him $200 each year to do that and to store it (and still had the same problem in the Spring although in prior years blowing compressed air caused it to start "peeing" again).

I have ordered a repair kit and the manual.

If I gotta mess with it each year anyway, I figured I might as well learn how to do it myself.

 

[TGuy]

Re: 15 HP Tohatsu Water Cooling Problem

sorry, the formula is proprietary and if I gave it to you I'd have to kill ya.

once you've done it, you'll see that it's really not that difficult to do. The service manual will be a big help and of course if you have problems, you can always post the question here and someone will give you some pointers.

 

[TANSTAF1]

Re: 15 HP Tohatsu Water Cooling Problem

Just an update my peeing problem. I re-blew air into the water cooling discharge piping and that resolved my problem. However, in the meantime I had already ordered the replacement parts and kit and a manual.

Here are the pages from the manual showing how to check the cooling system. Interestingly it shows a thermostat which I didn't think my 9.8 hp model had. Anyone know for sure? I don't always believe what I hear or read.

Also, I also scanned the whole manual. There is no copyright in it, so I assume it can be freely distributed. If someone wants a copy email me (do not PM me as I do not frequent this forum. Email address is "my user name" at fastem dot com. (Make the appropriate substitutions. The manual is about 4 MB so make sure the inbox of the return email you provide is able to take attachments of that size.

 

[TOHATSU GURU]

Re: 15 HP Tohatsu Water Cooling Problem

The manual is copyrighted...Whether you have it printed on your "copy" of your manual or not so do not distribute it. Copyright violations are one of the few things that Tohatsu will react to legally and you do have a thermostat on your cylinder head at the top.

 

[gss036]

Re: 15 HP Tohatsu Water Cooling Problem

I see in the instructions that they talk about running the motor while attached w/flushing adapter to the motor. I find that odd(?) as my new Honda specifically says not to run the motor while using the hose fitting that it could damage the motor, and to use muffs to run the motor to flush. I wish the Honda was that way because I would rather run the motor.

 

[TANSTAF1]

Re: 15 HP Tohatsu Water Cooling Problem

Last Fall, I flushed mine with just muffs and no fitting - maybe that's what caused the problem? I don't see how though. What if I just put it in a 55 gallon drum of fresh water and ran it? How is that different than muffs?

 

[TANSTAF1]

Re: 15 HP Tohatsu Water Cooling Problem

So this year I took it to a different dealer and when I started it up I got a strong steady stream of water out the pee tube. Yeah! So then I took it for a short spin for a few minutes at slow speed and then a few minutes at high speed. I checked and now there is no water coming out. So I slowed down to start up speed and limped back to the dock. I was running steady and smooth

I see from posts above that this has a thermostat.

Does it only pee at start up and when it's hot and the thermostat opens and lets water flow, or

Should it always pee? I think it should always pee, correct? That's was the manual implies. If it doesn't pee then there's a problem, correct?

So the thing has got clogged up or the impeller crapped out in 10 minutes? This is getting to be a PITA as it is not that convenient to lug an air compressor and power line down to the water.

 

[pvanv]

Re: 15 HP Tohatsu Water Cooling Problem

Yes, it should discharge all the time, regardless of whether the thermostat is opened or closed. The pee indicator is just that -- an indicator that the cooling system is pressurized. The motor can cool just fine with a clogged pee tube, assuming everything else is OK.

If you're on the water, and want to clear a clogged pee tube, have the engine running, and slip a stiff wire into the pee fitting and that will probably clear it. Keep in mind that if you have a bit of debris in the rubber hose that is bigger than the plastic nipple, it can be captured in the tube, and re-clog the nipple. That may have been your problem all along. If that's the case, you can temporarily remove the nipple and the debris will be flushed out when running.

Some people have even deleted the plastic nipple entirely, and just let the tube stick through the lower cowling, but that may require a longer tube and/or drilling the hole in the cowling a little bigger.

 

[TANSTAF1]

Re: 15 HP Tohatsu Water Cooling Problem

Thanks for your reply. I called a Tohatsu dealer who confirmed that it should discharge all the time. They said this problem was common when the motor is not used frequently. Sounds like Tohatsu should redesign it. This is my first four stroke, but I never had this problem with two strokes. At a minimum Tohatsu should amplify solutions to this problem (other than their only recommendation to take it to a dealer) in their troubleshooting chart to help people deal with this.

I used an air hose to clear it and it did - again for only two or three minutes. The next time I used a piece of wire and stuck it down the tube until it met resistance. That seemed to do it for good. Since we have finally got some good weather the boating season has finally started and it will see some more use and hopefully will not reoccur.

However I am adding a long piece of wire to my tool kit.

 

[CT sailor]

Re: 15 HP Tohatsu Water Cooling Problem

However I am adding a long piece of wire to my tool kit.

Yeah, but what if the pee tube isn't the only part of the cooling system that is clogged?

My 2007 Tohatsu 9.8 just started having "pee" problems this week and I'm pretty sure it's salt throughout the system. Pee is weak, it won't power up to full speed, and it runs a little rough once it's hot - 5 minutes or less with load on.

So my solution for now is to try to flush for 5 min with the ear muffs and cross my fingers.

Also - re: the copywrited service manual - I bought one and for $30 I expected a complete manual - why do they only tell you 30% of what you need to know to service these engines? Why bother?

 

[Tambourineman]

Re: 15 HP Tohatsu Water Cooling Problem

Other years when I had the peeing problem I did the ear muff flushing for up to five minutes with no luck. I don't think fresh water will work any better than salt water once its caked on. The thing that worked for me was using an air compressor. I used the wire this time as I was already in the water and not near a power outlet needed to run a compressor.

I wonder if there is some benign chemical that could be flushed through that would better dissolve the caked salt crud? It probably could be applied by one of the attachment to a garden hose for spreading weed killer.

The thing that irritates me is that each year I have paid money to have my motor winterized which seemingly would include flushing sufficient enough to prevent this problem.

I wonder if there is some sort of lubricant (silicone?) that could be sprayed or dribbled down the pee hole in the Fall (after a thorough fresh water flushing) that would prevent the problem in the Spring.

Anyway on the manual, it's very amatuerish and as well as in my (non-mechanic) judgment not very complete.

 

[pvanv]

Re: 15 HP Tohatsu Water Cooling Problem

We sometimes find that a bit of crud gets past the strainer, or crystals grow a little once inside the motor (we also have had this happen with freshwater zebra mussels), which enter as microscopic "seeds", and then grow to adult size inside the cooling system. Of course the heat of running kills the little buggers, and then they are basically a chunk of calcium stuck inside the cooling system.

Regardless of the nature of the debris, the thing is that it may be too big to clear the plastic nipple at the discharge end of the pee tube. If that's the case, pushing it back with a wire may just delay it re-clogging the pee tube nipple again. If you suspect that to be the case, remove the plastic discharge nipple and let the system flush the debris out of the bare rubber tube.

Compressed air to the pee tube can be a good solution, but again, if the debris has grown inside the cooling system, it may not fit out through the inlet strainer -- or for that matter, the pee tube nipple. In essence, it can be "captured" inside the cooling system. It may, however, get broken up into smaller bits that will fit through.

If you think that you have a chunk of crud that is captured in the cooling system, the best bet is to remove the powerhead from the base, manually clean the cooling inlet manifold in the bottom of the block and the top of the exhaust housing, then reassemble with a new base gasket. Acids and other solutions may work, but also may be too aggressive, and could damage the metals of the engine.

 

[Ags8th]

Re: 15 HP Tohatsu Water Cooling Problem

I just picked up a used Nissan 3.5 (NS3.5A) and ran it over the weekend. There was no visible pee stream, but the engine ran well and didn't seem to get overheated.

Today I was trying to get the drain tube clean and it was clogged at the nipple. (Actually - the nipple corroded away inside the rubber and is still in the engine) Should I drill the nipple out or leave it alone and hope for the best?

 

[pvanv]

Re: 15 HP Tohatsu Water Cooling Problem

The (old) 3.5A 2-stroke has a completely different p-tube setup from the 15 4-stroke. On the 15, there is a plastic nipple at the discharge end of the 1/4" ID tube. The 3.5A doesn't have one.

The bottom of your block (actually the top of the driveshaft housing), where the 1/8" rubber tube is supposed to connect is probably corroded. I would want a p-tube indicator, though it will run OK without one, as long as it is pumping. But, sans p-tube, how can you be sure, before it overheats?

Since the block is already corroded shut, clearing the p-tube area with a small drill shouldn't hurt, but you won't be able to reattach a rubber tube, since that part is already missing.