F150 yamaha - Water impeller gone - Oil in Exhaust

[Vossie]

Hi there I need some help to determine if my outboard is still in good shape (2012 model, 200hrs). Today I started it up with the water muff on only to get the high temp alarm before the tell tale start squirting water, so I turned it off right away.
I checked the thermostat, all open (warm) and bone dry. So I dropped the lower leg, only to see the impeller and pump is toast. More concerning was the puff of smoke at startup and the oil droplets in the exhaust. I'm concerned the motor overheated at some point.
I would like to do a compression test, questions are:
Can I crank the motor with the lower leg off to do the test? Will anything happen with the gear selector pin or something else moves and prevent me from getting the leg back on?
Or should I consider a leak down test?
If oil enters through the exhaust what will the plugs look like? Wet with oil? Carboned up?
Also is the "narrow" section suppose to be there in the drive shaft?

I ordered the service manual for the motor, just waiting on delivery.
Thanks for the help.

 

[Christl Waters]

It does not take long to wipe out an impeller if there is not enough water flow through it. So hopefully you might have gotten lucky. Did you put engine in gear before dropping the leg? If not, it can get tricky putting it back together. You cannot run the engine without the water pump, as it will be the kiss of death. You can "bump" it to check compression. It does not cost much or take too much time to replace impeller, so I would do that first. I would recommend getting complete kit with impeller, housing, gasket, impeller plate, etc. Use waterproof silicone grease for installation and not silicone sealant.

On your next test run, make sure you have sufficient water pressure to your muffs, to prevent this from occurring again. First prize would be to put engine in trough, or take it to nearby launch. Another issue can be the small pieces from the destroyed impeller getting into your auxiliary water cooling lines. I have seen this before, and it can be a pain in the a** to get them all out.

Feel free to PM me if you have any questions.

 

[Tightlines22]

Do you recall how it ran the last time you were boating? Was there any overheating then or previously?

As suggested replace the impeller and housing now. A compression test is fine to do with the lower leg off. Do you have lots of oil in the OB now? Checked the dipstick? At some point you have to determine where the oil is leaking from.

 

[silversands]

Did you use actual water muffs clamped on to lower leg...or did you try running it on the flush attachment? If flush attachment only that might explain the overheat/ lack of tell tale water....

 

[gungadin]

Newer yamahas have additional water intake holes for the water pump besides the main ones that the ear muffs cover. Cover them with duct tape before running on muffs.

 

[CIVANO]

Buy a stock tank to run the motor and forget the muff issues

 

[Vossie]

Thanks for the responses. I use clamped on muffs, after that I ran it in a tank submerged to above the water intake. there is no flush attachment on my machine, only the flush line at the top to flush the power unit, which I do not use while the engine is running as per the manual.
Oil level is correct.
As for how the boat ran before this, there was no high temp alarm, I cant recall about the tell tale.
So just to be clear, I can crank the motor to do the compression test with the lower leg off?
I hear what you say don't run it without the water pump so that means I will not warm up the motor before the compression test, will that affect the test results enough to give me a false pass?
If it will then I will replace the water pump first, run the motor, monitor and then do the compression test.
Also can someone help me with what the compression should be for this motor? F150 XA 63P 1121747
Thanks

 

[profisher]

You can do a compression test without the leg and with it being a cold engine. You are not concerned as much about getting an optimum high compression which a warmed up engine would give..you are looking for a cylinder being more than 10% off in compression than the others. So if a warmed up engine gives you 140 psi straight across all cylinders and a cold engine gives you 130 psi straight across all cylinders you are good in both cases. Again don't worry about what the psi is so much, the important thing is that are all close to each other. When you do a compression test remove all spark plugs first, kill the ignition by removing the dead man lanyard, open the throttle fully then roll the engine over so that you get a couple compression cycles per cylinder tested. When you go to re install the leg you may have to have someone help you spin the prop (in gear) to get the splines to line up again into the crankshaft. Not a big deal.

 

[Vossie]

I read these forums often for advice and help, super helpful. But not often enough do we finish them off with the final conclusion.
So to conclude my situation above.
I followed Christl Waters advice and did a compression test, with the leg off, and found that the compression was in spec. Sigh of relief. I received the water pump replacement kit and replaced all the items. I was a bit concerned about a slight abrasion on the shaft. I flushed all the debris out of the water lines. Start it up and it pumped all fine. Its now going into its third season on my watch and I'm almost at the next 100hr service with no issues.
One thing I do now is not use the water muffs, find that you need a lot of water pressure to prime it all, so I have a dunk tank.
I also see the puff of smoke after a long stand, say 2 months. I read on another forum this is coming from the bottom cylinder, since the oil run down the inline 4. I also store my motor fully trimmed in to protect the pushrods on the trim system. That leaves the cylinders tilted down and oil run into the bottom cylinder causing the smoke. Good thing is I have no oil consumption.
One extra feature I did was to tap into the alarm line in my 703 control and wire a RED LED flashing unit on the dash, since my hearing is not 100% anymore and at plane in the ocean there is no way I will hear the alarm.

 

[profisher]

Your best insurance against overheating is adding a water pressure gauge for your dash. Simple installation and will give you the chance to shut down the engine as soon as debris clogs the water inlet and way before the alarm sounds. I have one on my boat and I keep an eye on it when ever running shallow water around eel grass, or when running through a tide line or if I get into bull kelp. It has saved me more than once. Probably the best $75 you will spend.

 

[Christl Waters]

Your best insurance against overheating is adding a water pressure gauge for your dash. Simple installation and will give you the chance to shut down the engine as soon as debris clogs the water inlet and way before the alarm sounds. I have one on my boat and I keep an eye on it when ever running shallow water around eel grass, or when running through a tide line or if I get into bull kelp. It has saved me more than once. Probably the best $75 you will spend.

That is a great idea. What engine(s) did you do this on?

 

[profisher]

200 Yamaha 2 stroke...but can be done to any engine. On mine there are two pipe thread plugs...one on the top of each head. I just removed one and bought a same thread fitting with a hose barb on one end. The gauge comes with a long length of hose so get a fitting for that diameter of hose. Zip tie it to the fitting, fish the hose from the engine to the dash and mount your dash gauge. On some engines (without a removable plug you may have to drill into the block to a water jacket and tap the hole to take the fitting. If that is daunting have a shop do the drilling and tapping for you...the rest you can do yourself its just time fish wiring the hose to where you need it.

 

[Christl Waters]

200 Yamaha 2 stroke...but can be done to any engine. On mine there are two pipe thread plugs...one on the top of each head. I just removed one and bought a same thread fitting with a hose barb on one end. The gauge comes with a long length of hose so get a fitting for that diameter of hose. Zip tie it to the fitting, fish the hose from the engine to the dash and mount your dash gauge. On some engines (without a removable plug you may have to drill into the block to a water jacket and tap the hole to take the fitting. If that is daunting have a shop do the drilling and tapping for you...the rest you can do yourself its just time fish wiring the hose to where you need it.

I will look into that. Thanks for sharing.

 

[sly_karma]

Etec has a transducer kit for water pressure, data is viewable on NMEA display or iCommand gauge with all the other engine info. I went the geek route and found a generic 0-30 psi transducer on Amazon, fittings and Deutsch plug at Lordco. Cost $30 vs BRP kit at $150.

 

[ship happens]

I will say this. The electronic water pressure sensors and data viewing on display is not as accurate as you think. Sometimes it is. They fail alot. The mechanical Faria Guages with the solid water line is pretty rock solid.