Yamaha 115 4 stroke Impeller

[andyjcox1]

Hi I think I know the answer to this but just in case there is something else I can try...

I have a 2004 Yamaha 115 outboard. On my last trip out, everything was fine and there was a good tell tale from the engine. However, upon fitting the flush muffs on the drive to flush it out, there is no tell tale. I have given the outlet a clean, sucked/blown in case of blockage etc.

I also flushed it out using the flushing fitting and water seemed to be going all the way through. The engine is also not making horrible noises or getting too hot, although I am not running it for more than a minute just in case.

I can only assume the impeller has had it, or could there be something else. I am secretly hoping if I put it in the water and run her up it will start to work, but I don't want to do any damage.

Cheers, Andy

[paddlers]

Never had much joy with muffs, have you tried it in a tub ?

[Festinghouse]

my force 120 wont flush on the muffs, yet pumps perfectly in the sea. i find it strange as it has a mercury gearbox - my mariner 75 always worked on the muffs. i will of course be checking the whole water pump etc over winter to see if i can find any fault.

[paddlers]

One of the most enjoyable aspects of owning a boat for me is the tinkering either on the craft/trailer or engine.
There's not a lot of difficulty removing the gearbox to get at the impeller & provided you've got basic tools most jobs are manageable. I draw the line personally at stripping the gearbox out or the carbs but most jobs are fairly simple !
New thermostats & poppet valve gasket on mine recently. There's a wealth of experience on this forum.

[paintman]

Sure there is enough water being delivered by the hose?
As has already been said, get yourself a tub - domestic cold water tank/dustbin/plastic tub - & see if that makes a difference. Seems to be a far better way of telling if the impellor is working.

[colcreate]

Sometimes muffs and low hose pressure are just not enough to get a strong telltale. In a tub or in the sea mine is fine and has a good strong stream from the telltale. Pull it out put muffs on it and it takes ages before anything shows unless I rev it then it seems to spurt out. New impeller installed at the beginning of the season and clear waterways throughout. Just seems to be one of thos things.

[j.i.wilson]

I have the same problem (or symptom) on my Honda.

It's normally due to insufficient water from the hose.

I certainly wouldn't worry until you've tried it either in a tank or at sea.

I'd you use a tank make sure it's deep enough. My manual says the water level must be 4" above the cavitation plate.

Ian Wilson

Sent from my HTC One X using Rib.net

[jyasaki]

Use the hose connection at the top of the bracket on the port side. Works fine and no need to start the motor.

jky

[andyjcox1]

Thanks all, it gives me abit of confidence it may be OK. I flushed it usung the hose connection and it seemed to flush through. Going to get a big bin and try that. This thread may just save me an expensive trip to the engine doctor for nothing.

Andy

[jyasaki]

Don't judge impeller operation from running on muffs. Too many outside variables: fit of the muffs, water pressure from the hose, flow rate through the muffs.

Put it in the water (barrel or stream or ocean - neighbor's fish pond if they're away for a bit) and start it up. Should start peeing in a few seconds at idle speed, bit less if the revs are up.

jky