9.9 water circulation problem

[Allen Boice]

I purchased a 1991 Yamaha 9.9 four stroke that hadn't been ran for 2-3 years. The motor runs fine, but won't pump water. I put in a new water pump, but still no water. It appears that there may be a plug in a water jacket someplace. Anybody have any thoughts about this issue? If the block is in the water jacket is it even worth fixing?

[99yam40]

How do you know it is not pumping water? no tell tail or over heat?

[Allen Boice]

Correct, no water pumping. I tried to blow the system out with an air hose and no luck either. The bottom water spicket on the manifold is clear, but the top one appears to be plugged someplace inside. I can't blow air through it or force water through the engine.

[bumperfood]

when you took the waterpump off were the vanes in little chunks?

[Allen Boice]

No, I believe the obstruction is probably corrosion from use in salt water, but I could be wrong. Is there anything I can put in the hose on top that will disolve the build up, if that's what the problem is?

[bumperfood]

I think I would remove the leg again and then remove the thermostat, you may find salt deposits here. I would use a garden hose to run water into the thermostat opening and see if it runs out the water tube in the leg. I would also run the water up the water tube into the block and see if it flows out the thermostat area. Be cautious removing the two thermostat bolts, they may either be corroded or seized in place by salt. In either event you may break them off in the process of removing. If you get a good flow of water, you may have missed something when replacing the water pump.

[rodbolt17]

typically with salt water motors of the f/t 9.9 you have to pull the head and exhaust covers and manually ream out the passages.
especially the two from the block to the outlet nipples on the port side of the head.

[Allen Boice]

Thanks guys these are good starting points. I't will be awhile before I can get to it, but I'll let you know the outcome.

[Allen Boice]

I took the thermostate out and water runs freely through the water pump tube and out the bottom of the tower. Water won't go through the top water jacket so it looks like it may need a major overhaul to get it unplugged. Probably a job for a Yamaha mechanic. I think I see a new kicker in my future.

[rodbolt17]

if the two 6mm bolts(10 mm head) on the port side of the head come out.
its a dirt simple job just takes time.
remove the head,remove the ex covers clean, reinstall with new gaskets an orings.
or buy my 1998 25" shaft electric start tiller T9.9.
new head and new carb.

[Allen Boice]

Thanks for the tip the help here has been great. And thanks for the offer on the 9.9, but if I do get something different it would probably be a new 9.9 with power trim. I've had two of them in years past and really liked the power up features. I do a lot of Fall salmon fishing in Southern Oregon and we fish one way with the tides which requires lot's of up and down with the kicker. Power trim sure makes it nice.

Thanks again, Allen

[Triumph150]

If the outboard has a thermostat doesn't it shut off water circulation until it reaches a certain temperature or should there always be water coming out of the telltale? I just purchased a used 98 9.9 myself and having the same issue. Waterpump looks good just no water coming out. Don't want to run it and find out I'm wrong.

[bumperfood]

Water should come out of the telltale, whenever the engine is running. It is an indicator that the impeller is pumping water.Best if you find out and repair the problem before using the engine on your boat.