Can't get outboard motor to pump water on muffs or in drum!

[Cowboy57]

Maybe this has been answered here on the forum before, but I can't find it if it has. My motor is a Yamaha 150, and I cannot for the life of me get it to pump water on the muffs or from a drum. The muffs I have are the "good ones" that supply water to both sides of the intake. I sawed a plastic drum in half and tried that as well, and it just sputters a little water out of the pee hole every now and then. Afraid to run it too long as I don't want to burn up the impeller or overheat the motor. I bring it to the lake and put it in the water, and within 8-10 seconds have water pouring out the pee hole with good water pressure. Can someone explain to me what is going on, cause I'm at a loss trying to figure this one out. Thanks in advance!

[alli ss]

If water is coming out of the exhaust its fine. You never want to run above idle on the muffs anyway

[snapshotmd]

Perhaps you're not immersing the LU deep enough in the tub? Is there minimum leakage around the muffs?

[huntnfishrig]

I dont have a solution but my vmax 225 does the same thing on muffs or in a bin. I put a new pump in for good measure and it also does the same thing. I stopped worrying about it. Drop it in the lake and it pumps great.

[61Woody]

I have a 25 Merc that does that also, worries the hell out of me but put her in the lake and she pees like a horse.

[Gray]

This sounds too simple to believe but I had same issue so I took to mechanic and he took the muffs and pressed them together really hard for about 10 seconds and then tried them and the motor peed like a race horse. I've been doing that each time and never a problem again. It's worth a try since it's free.

[railey]

I have a 2.5 mercury that does the same thing...no idea why

[BMCD]

All my engines have been able to push water out. If your muffs are not tight it will struggle. Just had my Dads 150 EFI the outlet hose was clogged.

[DrewFlu33]

On the older Mercurys at least, I know why many won't see them "peeing" on the muffs: They have to reach a certain temp before they start pumping water. Mine takes over 2 minutes of idling on the muffs before it starts pumping. To be fair, this is Minnesota water where our pipes are buried 8+ feet and the water still comes out cold in the middle of the summer, but the point still stands. Most folks don't let their motor idle for long at all on the muffs.

[skeeter91]

the motor wont pee until the thermostats open,120-*140* water temp.if the muffs dont seal well,it doesnt pull much water.there is also a vent on the rear,lower part of the mid that wont allow the motor to build up water pressure if its exposed,thats why it pees when in the lake,the vents are submerged.

[iabass8]

Get some of those long arm 'c" clamps and clamp the muffs tighter to the LU and make sure the water is shooting right into the intake. It doesn't take much extra pressure to seal those muffs. Put them on your motor once and gently press on one side and you will see what I mean.

[billnorman1]

If there is any way to get air into the intake area the water pump will not pump water. You could have a leak in the pump intake area. If she pumps on the water you should be O.K. but if you find someone with a similar motor, you should ask them.

[mcmanucr]

Have you tried trimming the motor way up while the motor is running with the muffs on? This has solved the same problem for me in the past. Once it starts peeing I trim it back down. Not sure if you have tried this or if it will help but I thought I would mention it.

[Lil Mo]

My 40 Merc on my tin rig does the same thing. On the muffs it barely drips water out the indicator. When in the water it pumps with strong pressure. I even installed a new impeller and it does the same thing.

[Go Loco]

Does your motor have a thermostat? If so, then it has to warm up a little before it pees. You might check for obstructions in your pee hole too. (Sorry)

[brucekgreen]

I have heard on the mercury anyway they dont pee much at idle just like the old vacum system on motors for you wipers if ide is slow wipers run slow speed up so do wipers for the outboard motors reason i dont know.

[Bass Junkie]

Your putting cool water into the engine and the thermostats haven't opened yet. Also, if you have a Yamaha you can just use the hose fitting on the side of the engine, you don't need muff or that tank.

[alli ss]

Your putting cool water into the engine and the thermostats haven't opened yet. Also, if you have a Yamaha you can just use the hose fitting on the side of the engine, you don't need muff or that tank.

That fitting is for freshwater flushing not running the engine. It doesnt supply water to the impeller so youll burn it up. It will keep the block cool tho

[Rich Z]

OP asked about yamah so heres the correct answe. The Yamaha owners manual states not to run your motor on the flusher hose yet its perfectly safe to do so. The flusher hose and water pump plumbing both are connect at adapter plate and ample supply of water will drain down and cool the impeler. You will see water running out from water pick-up and motor won't overheat using the flusher hose as long as it's only ran at idle speeds. Additionally, the pisser on Yamaha is before the t-stats so it will pee soon after the water is turned on unless the pisser hose is clogged up. Take the ear muffs and give it to Merc guy lol.

[tracer1]

If the muffs are the Yamaha red (orange-I'm color blind somewhat) they have to be on real tight & flush with the intake. Used to tape mine on real tight. Quit using the muffs & bought a watering trough from Tractor Supply. The water has to be over the cavitation plate completely. Don't know if that will solve your problem but if it pees normally at the lake, well, that should answer your question about that something is wrong with the muffs or tank.