1975 Evinrude 9.9hp - leg fills with water up to the top

[fishon71]

I have a 1975 Evinrude 9.9 hp that when I run it the leg fills with water so high its getting into the cylinders - seems like the water is not getting out fast enough. It has a new water pump, head gasket and thermostat gasket. The thermostat has been removed. There is no thermostat installed.

 

[raczekp1]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

when you instaled new water pump i think you put wrong water pump gromet. http://www.sschapterpsa.com/ramblings/Lower_unit.htm
or drain hole in lower unit is blocked.
if its Long shaft , there in 5" spacer is drain hole also-can be blocked
there should be instaled termostat, becouse you will not warm up engin block to get ful operaing mode.
my advice is to drop lower unit , atache garden house to water pipe leading to powerhead and run water and start engin and look if water is enetring to cylinders.
when you put new head gasket, did you plan(flattening)head surface?
you should do it.
in 3 motors i had to remove 0.4mm of head surface

 

[jmendoza]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

As mentioned, use the smaller water tube grommet, not the one with the large cone shaped end. Use the one in the middle(see photo). But, even so, the water should overflow out of the top of the exhaust housing at the exhaust releif hole, and out the holes above the cavitation plate. If it is not, blow out the hole with compressed air once the exhaust housing has drained. You need to replace the thermostat for the engine to run right, otherwise it habitually fouls plugs if you run it at low speeds because it over cools and never warms up. If the engine is run with no thermostat in salt water for any length of time, the sealing area in the head where the thermostat goes will corrode out and then will not seal properly, and over cool; mine was this way and I made a thin washer out of aluminum and pressed it in place with some Three Bond 1104 sealant. Once you have that sorted out, it should give you many years of trouble free service, mine has run every season since 1980. Unfortunately, the 1977 and later 9.9 and 15 engines are not as reliable because the solid state ignitions are unreliable and seem to eventually fail.

 

[fishon71]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

Ok thanks - here is a little more info. This was a long shaft converted to a short shaft - I found the small drain hole where the shift shaft is clogged and full of salt. This area was holding water when I removed the lower unit. It also looks like it has the large rubber grommet on the pump housing. I think it needs the big one because the water tube is pretty big in diameter, looks like a match to me. Can having the little drain hole clogged cause water to rise in the leg?

 

[rolmops]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

If water gets into the cylinders,you have a different problem. Water gets into the cylinders because of either a blown head gasket or blown exhaust seals.
That would point to a possible blocked water cooling system but there are more possibilities as to why you blew a head gasket.
My advise would be a total overhaul of the cooling system and replacement of the seals and gaskets,including the seals on the top and the bottom of the crankshaft.
You should do a compression test on the engine.Low compression in one cylinder or both often points to a blown head gasket

 

[jmendoza]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

The larger grommet is for later models, thus it is included in the "universal" water pump kit for all years. The way the 1974-76 mid section/exhaust housing drains is via the oversized hole the copper water tube passes through at the bottom. If you use the larger grommet, it seals against the surface the water tube passes through does not allow the water to drain. I discovered this myself the hard way, as mine did not drain when I used the larger grommet. My engine is a 1975 as well. It took me a while to figure out there is no drain hole per se...it's just an oversize hole the copper tube passes through.

There are no instructions in the kit that tell which water tube grommet goes with which year, but I can tell you from experience that on the 1974-76 versions, you must use the smaller grommet.

 

[raczekp1]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

i instaled this larger water pump gromet in my 9.9 83' but i driled 2 extra holes(6mm dia each) in bottom of midcection surface(this place where water pipe is protruding).

termostat is also alowing to fulfill water around cylinders.
when you run motor termostat normal mode is locked, but water is floating to chmber where cylinders are placed, more and more,
water is filed and temp reach 65 deg celcius and termostat opens to allow hot water to flow out from motor and cool water enders instead this hot water.termostat is becoming cool and is locking.

when you remove termostat, water just enters and flow out from motor and upper cylinder can not be cooled becouse water enters and just in time flow out

 

[fishon71]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

Update - cleaned out drain hole and 3 inches of salt now it drains okay, used smaller rubber grommet 0n water pump outlet. I still get a lot of water in the leg and if I pull the spark plugs after running a while they are a little wet with water. Keep in mind the head gasket was replaced too as I thought for sure that would be the fix.. Motor seems run okay but it appears water is getting up into the exhaust some how.

 

[OptsyEagle]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

When you say the motor seems to run OK, are you boat testing it or barrel testing it. The reason I ask is that if water was getting into a cylinder it may possibly have killed that spark. If you are running it in a barrel with only one good cylinder you probably would not even notice it but on a boat you would observe a severe loss of top end power.

To test the motor in a barrel you could fire it up and with insulated plyers, disconnect one spark plug boot at a time. The motor should run OK on just one cylinder, so if it quits when you pull a plug boot you would then assume the other cylinder was never firing.

There will always be water in the exhaust from the exiting cooling water shooting down and there is also water around the leg as well. That drain hole you cleared out will also bring water in when it is submerged. This is all normal.

 

[fishon71]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

It will run on one cylinder at at time either top or bottom. If I remove the plugs there is always a little water on them (both top & bottom)

 

[rolmops]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

If water gets into the cylinders,you have a different problem. Water gets into the cylinders because of either a blown head gasket or blown exhaust seals.
That would point to a possible blocked water cooling system but there are more possibilities as to why you blew a head gasket.
My advise would be a total overhaul of the cooling system and replacement of the seals and gaskets,including the seals on the top and the bottom of the crankshaft.
You should do a compression test on the engine.Low compression in one cylinder or both often points to a blown head gasket

Apart from the above. when you took of the cylinder head to replace the gasket,did you lay it on a piece of glass? This trick would have shown you whether the head is slightly warped or just flat.Another very important part is tightening the bolts in the right cadence and to the right torque specs. Water will enter the cylinders along the head gasket during the downward stroke unless there is a perfect seal.
I mentioned the top and bottom crank shaft gasket because if water splashes over the cover it will get sucked in the block past those gaskets and specially with salt water you will end up with rust in your crank case.

 

[fishon71]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

Do you mean crankshaft seals? One on each end of the crank?

 

[OptsyEagle]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

OK. When you replaced the head gasket did the cylinders look OK. Any indication of water. Also a question was asked in post #2 about re-surfacing the head before you torqued it back down. Was this done?

The reason I ask is if water is getting into the cylinders there are not too many places where water might enter both cylinders, except the head gasket area and possibly an exhaust gasket. Have you taken any compression numbers after you changed the head gasket?

 

[fishon71]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

All internal parts looked fine and head was sanded flat. Compression was about 120 in both prior to head gasket did not check after. I noticed water collecting around the exhaust hole on the bottom cylinder which made a slurry type mixture (with head off) and this stuff also oozed out of the exhaust when shut down. Where is the exhaust gasket located?

 

[OptsyEagle]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

There are two exhaust cover gaskets on the starboard side that I am pretty sure water circulates through. You can see them in the water circulation picture below (ignore the overboard water indicator).

Backtracking a little here. You first said that water was building up in the motor due to a blockage of some sort. If water made its way up to the bottom of the powerhead it would probably make it through the lower crankcase seal that is behind the part indicated in picture 2. Those seals weaken after 36 years but in any event it would only effect the bottom cylinder. Did you remove the cylinder head and observe the water before you cleared the blockage or after? Perhaps water is not getting in there anymore if it is not building up in the leg.

It would probably be a good idea to do another compression test to see just how well your head gasket and re-surfacing job is working. I can see the info being very useful, be it good compression or bad.

 

[jmendoza]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

If the exhaust releif hole at the top of the mid-section housing is clogged, pressure can build up inside and force water into the exhaust tube, causing it to enter the cylinders. You said the engine was converted to a short shaft, and if when this was done, the seal on the bottom of the exhaust tube was lost, damaged, or missing, then water will be able to be forced up the exhast tube. A clogged exhaust releif hole can also cause the lower exhaust tube seal to fail.

 

[omcnut]

Re: 1975 Evinrude 9.9hp - leg fills with water up to the top

had the same problem with my 88 9.9 after the first time i changed the water pump it was also a converted longshaft and i used the larger grommet annoyingly the pump leaked requireing the lowerunit to be removed again......also all my 9.9/15 jhonnyrudes ive modified bt drilling out the lowerunit drain hole to 7mm/1/4" to get all the saltwater out as ive had a couple with such bad salt build up it has blown out the side of the gearbox where the selector shaft runs!!!