1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

[Jerry_NJ]

I thought I put a post up on this subject yesterday, seems not. Since I have downloaded a 1998 Yamaha 9.9 User manual, there was nothing available on anything older - I can see differences physically between my Yamaha and the 1998, still I assume from other experience I have with OMC outboards that the 1995 Yamaha has a pilot hole which shoots a stream of water out easily visible to the operator to let it be known that the engine impeller is circulating engine cooling water. The 1998 manual shows the pilot hole to be on the engine lower pan and on the right had side (looking forward from behind the engine). This manual also states that the operator should check for this flow which must be present anytime the engine is running (any gear) and the lower unit is in water.

I have a new looking 1995 Yamaha that I took to the lake for the first time yesterday. I purchased knowing the engine was very low hours and had not been used in many years. I made the argument on my offer that the engine appears to be low hours, but that doesn't make it the same as new, in fact I suspect the cooling water impeller may need to be replaced. This was taken into consider on my purchase so I am not disappoint if I have to replace the impeller.

But, here's what happened at the lake. It was a cool and cloudy day with the air temp about 60 degrees, I'll guess the water was closer to 50 degrees.

I started the engine and did not see the cooling confirmation stream. I shut down and mentioned it to another boater who was launching a boat with a newer 4 Cycle Yamaha. He said he also owns an older 2 cycle and said that engine has a thermostat and shuts the water off until the engine gets up to temperature, at least a couple of minutes. He asked if my engine was overheating from the brief time I had it running. I said no. He said let it run for a few minutes. I removed the cowling and started the engine (easy starting engine, and quiet) and let it run. After a few minutes I splashed a few drops of water on the engine, the water just ran down the side of the block, no steam, nothing even suggestion hot. I shut down and touched the block with my hand and it was no more than a little warm. So I started the engine up and ran it for perhaps 10 minutes getting to a backwater area where I could operate on my electric motor and fished for 20 minutes or so. I then restarted the engine and returned to the launch area. Still no pilot hole water stream. I again checked the engine temperature with a splash of water and then with my hand.

I then looked for the water intake, which both my experience with other engines and the 1998 manual, on the lower transmission housing, on either side just above the anti-cavitation plate. I didn't see any, the only intake lookiong area I saw was on the bottom of the anti-cavitation plate.

I also noted a hole in the back of the lower unit housing just below the engine level that passed exhaust gases when the engine was running. At one point I though that was the pilot hole. I have to get back to look at the engine to see if I can find the pilot water jet hole.

Looking for advice on checking this engine out as far as the cooling is concerned. The engine runs well and is more quiet than my past OMC engines (best I can recall). Is it possible the engine is running cool without water circulating, or is it possible the water is circulating but the pilot hole is plugged. I can try to clean the hole, with what, a wire?

Again, I would appreciate a confirmation on the location of the pilot hole, that one should see a water jet any time the engine is running, and where the cooling water intakes are located.

Thanks,

 

[Jerry_NJ]

Re: 1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

Wow, almost a week an no replies. I must have posted a stupid question, or perhaps one poorly worded (most likely, and typos too, sorry) or us 9.9 HP Yamaha owners are a rare breed. Well, since there was over 100 who viewed my post I will give some information I discovered by posting some questions on the Evinrude/Johnson forum (I get inputs there even when I apologize for asking there on information I will apply to a Yamaha - well I do have an Evinrude too).

I still don't know the age of my Yamaha, it may be older than 1995, but as it looks new it is easy to examine the components.

Removing the engine cover I see a small hose about 1/8" in diameter going from the port side of the engine (the head and 2 spark plugs are on the rear of the engine) which I believe is where cooling water enters the engine. Tracing that hose (not difficult it is only 6" long) it goes to the "floor" of the engine compartment at the center rear. Looking below on the lower/transmission cover I noticed again the interesting looking port (hole). I ran a wire up that hole, didn't go far. I then removed the subject hose from the engine side an blew into it while holding my hand to feel any air coming out of the hole I just ran a wire into. I didn't feel any air coming out but I felt air on my arm. Taking another look at the outside of the engine floor I find a very small hole (no more than a 1/16" diameter) and find the air is coming out of there - I think I have found the pilot/pee hole. As there was no problem blowing air through, water should also go through. One of my questions answered.


It is still unclear where the cooling water intake is, but the only hole/screen big enough in my mind to handle that job is on the lower side of the anti-cavitation fine on the lower unit, just above the prop, making me wonder if that is a good location, lots of turbulence there when the prop is providing power. I took that screen off it was clean as is the rather large channel inside the lower unit. I could not run a wire up that channel as it turns back toward the drive shaft before going up, I believe that it goes up to the engine.

If any reading ared interested I will post a couple of pictures showing the hose and the pilot hole and intake as I located them.

 

[jspriddy]

Re: 1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

I'd check into cleaning the tell-tale hole, but I'm thinking I'd get this to a shop. It seems you have a very nice motor, and it'd be a shame to ruin it. I'll bet the impeller at that age is gone, as in completely.

I don't know about a 9.9 and the thermostat issue, but my 1994 25 hp 2 stroke will put out a stream immediately, even cold, IF it's submerged in water. It takes several seconds on water muffs. I don't know what the difference is.

good luck,

John

 

[Jerry_NJ]

Re: 1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

Thanks, I had several recommendations to change the impeller. One fishing relative on who lives on the gulf and puts a lot of hours on a big outboard (he had a 250 hp last time I went out with him) said I should change the impeller every couple of years as routine maintenance. When I thought about it I thought the impeller sitting dry in a stored engine might just "dry out", become hard... don't know.

I have owned a 9.9 Johnson circa 1986 (purchased new) that lived for about 10 years without an impeller change but wore out with what I'd guess is no more than 300 hours. I attribute that to the OMC recommendation of the time to mix gas oil at 75:1, I believe that was not sufficient lubrication. I replaced it with an Evinrude in 1996 that has been running on the same impeller, only problem with that engine was I had to replace the electronic ignition module. That engine and the associate 14' Gurmman ProFisherman fishing boat got whacked by Sandy when it hit the NE coast last October. That's what broght me to the "like new" Yamaha and an associated 14' boat by Discovery (an off-shoot of Grumman, now out of business, a deeper V, uses a long shaft engine).

I can say I find recommendation for Yamaha in several places that recommend 100:1 after a breakin at 25:1. Do you run yous at such low oil ratios?

The lack of inputs here on the Yamaha forum may be a result of there being a smaller population "out there" or the Yamaha is more reliable (in reference to OMC, say) and thus there are fewer people coming here to discuss problems. I always got several replies when I posted on the Johnson/Evinrude forum as as several other subject areas... but here on Yamaha your are the first and only. I go back a look at how many have "read", must be in the 150 range by now.

 

[jspriddy]

Re: 1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

I would guess the impeller dried out, became hard and basically went away when you first started it. As I understand, even bumping the starter with a dry (i.e., out of water) impeller, especially an old one, will rip the fingers off of it. I don't think the gas mix would be a factor, since the pump takes in fresh water directly, and would have no oil residue in it. Most people do recommend every two years on replacement.

I run mine at 50:1, but Yamaha does recommend 100:1 for my motor. I've been vacillating back and forth about going to 100:1, or at least 75:1. I think my motor smokes excessively at 50:1, and I believe Yamaha would know better than anyone what's best. After all, they have a vested interest in their motors lasting. And I have an air cooled weed eater that has been running 100:1 for years without any problem.

Maybe Yamaha's do have less problems. They are very popular here, and many consider them the best. From my experience, they are cold-natured, at least the 2 stroke engines.

John

 

[Jerry_NJ]

Re: 1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

Thanks, it seems my next problem is ordering the correct impeller, seems a model year is necessary, maybe close is good enough. The motor has an identification plate with a three field number that seem to be the model - it is a long shaft and I see an "L" in that series of numbers, but I have not been successful in finding a translation from those numbers to the motor model/year list.

As I mentioned, I ran the motor with a careful monitoring of the surface temperature of the block for about 10 minutes at moderate speed/load and with a full throttle for a few 10s of seconds just to see how hard it pushes. I stared and ran very well, albeit it seemed slower than my 10 HP Evinurde (about the same vintage) but the boat the Yamah is on is a deep hull and must weigh an additional 100 pounds or so. Both boats are aluminum, so lighter than F-glass. On full throttle and the older boat the Evinrude would throw an straight wake out the back, one with a defined center and waves going to each side. The Yamaha was more of a froth out the back, but that could be the "trim" was too high, the bow also seemed too high.

When I get this all worked out I will runf at a "thin" 50:1, I don't trust even the 75:1 as I think that brought about the early death of my 1986(about) Johnson. I still use TWC3 (is that the code?) "regular" oil, maybe synthetic 2-cycle would let one go toward 100:1 with some confidence. I bet there have been a number of discussion on iboats on the subject... I'll do a search.

 

[Toddboat]

Re: 1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

Just to further confuse the issue, I have a 2003 50hp Yamaha and when it's cold, it does not pee for about a minute. It scares me sometimes when I run it on muffs because I feel I should be shutting it down. But once it heats up, it pees strongly. Once heated up, if I turn the motor off and restart it while hot, it pees immediately on start up. So there may be some truth to the thermostat comment.
However, this does not solve your problem because running the motor for 10 minutes should produce a pee stream. I would not feel comfortable running any motor that long without seeing the stream. Why not just drop the lower unit to have a look? It will answer all of your questions about where the holes are and what the impeller looks like. I recommend changing the water pump as a kit, rather than just changing the impeller. I don't think the cost difference is all that much to buy the whole kit as opposed to just buying a new impeller. I believe the kit comes with a seal/gasket that should be changed. Make sure you install the new impeller in the correct direction. If there is enough of the old impeller left, remember which direction the vanes faced so that you can install the new one in the same way.

 

[jspriddy]

Re: 1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

Just to further confuse the issue, I have a 2003 50hp Yamaha and when it's cold, it does not pee for about a minute. It scares me sometimes when I run it on muffs because I feel I should be shutting it down. But once it heats up, it pees strongly. Once heated up, if I turn the motor off and restart it while hot, it pees immediately on start up. So there may be some truth to the thermostat comment...

Todd, have you tried running it in a tub or whatever of water? Mine starts the tell tale immediately (even stone cold) submerged in water, but on the muffs it too takes a while to start. What could be the difference?

Thanks,

John

 

[Jerry_NJ]

Re: 1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

Thanks, I'm still not certain what the model year is. But, a kit approach sounds like a good idea, hope it tells the direction of rotation... what happens when the transmission is in reverse? Doesn't that turn the impeller the opposite direction? I do recall seeing on Youtube the impeller bend/deformation.

I have taken to the practice on my Evinrude of dry starting it at home before I tow to the lakes - I would let it run only about 3 or 4 seconds, just to confirm it will start. But, the impeller was often dry, i.e., hadn't been in the water for days, maybe months.

I like the "tell tale" better than "pee", but it is the latter that I will remember : (

 

[jspriddy]

Re: 1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

The reverse and forward gears are in the foot, below the water pump. The shaft that turns the water pump always turns the same direction. I have taken out an impeller and reversed it with success, but that does nothing for age and deterioration. It can work in an emergency.

John

 

[Jerry_NJ]

Re: 1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

Thanks, guess the location of the gear lub fill/check and drain holes should have suggested something about where the transmission is. Is the GL5 the recommended gear lubrication? Again, I don't have the owner manual, or even know for sure what year the engine is. In the case of OMC I believe they have used GL5 in most outboards for years, surely back to the age of my 1995 model.

I have looked at youtube on the impeller change and think I also recall there being to long shafts that came along when the lower unit is pulled - the drive shaft (to which the impeller is locked) and the shift lever. Hope it isn't too difficult to "fish" those two shafts back up to the engine level, they must just slide into something - a gear in the drive shaft case (needs heavy gear lub before inserting?) and some simple latch in the shifter - wondering. I can look at the parts breakdown, which continues to be problematic is selecting the Model (a guess in my case, but any 9.9 2 cycle should work for a given year) when I go to a recommended parts web site. The site allows me to select Yamaha, and a year (tried 1994 and 95) and then a model, but the short list for a given year sometimes doesn't include a 9.9 HP, suppose there were some years Yamaha didn't make that engine? Sounds strange/unlikely.

I have been fishing on this subject in other forums here on iboats, so I have some other inputs. This being my first Yamaha it was my first need to come to the Yamaha/Suzuki Forum. I had no early replies, many lookers, but no buyers. So I went to other forums for general information/experience on smaller outboards. Speaking of Suzuki, I have a 2009 SX4, and now Suzuki no longer imports this car to the USA. It is a rather reliable AWD "Crossover" and I plan to keep it for a while yet, but it could be expensive to fix down the road. I assume Suzuki still imports outboards (can't say I recall ever seeing one) and motorcycles, seen a few of those.

 

[Toddboat]

Re: 1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

That may be the difference, I'll try running it that way next time to see if it pees right away when cold. Thanks -Todd

 

[jspriddy]

Re: 1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

Is the GL5 the recommended gear lubrication?

I have a Seloc manual for Yamaha's. I'll look and get back to you, but I think any of the commercial marine gear lubes (quicksilver, etc.) would be ok.

Hope it isn't too difficult to "fish" those two shafts back up to the engine level, they must just slide into something - a gear in the drive shaft case (needs heavy gear lub before inserting?) and some simple latch in the shifter - wondering.

That was an old Johnson 5 horse I turned the impeller on, and it worked. But that's been years ago, and there was a lot of Budweiser involved in that deal, so I wouldn't be one to advise you on this. Maybe someone else will jump in here.

Also, there are numerous threads on this somewhere. I have a hard time with the search feature.

John

 

[jspriddy]

Re: 1995 (est) 9,9 HP Yamaha 2 Cycle - No Pilot hole water stream

Jerry, the only thing my Seloc manual said was that Yamaha recommended their gear case lube or an equivalent SAE90 wt. I'd just pick up a quart or so of marine gear lube.

John