Problem with Yamaha impeller

[PeterM]

It is possible to fit the impellor up side down....(Don't ask how I know) all looks fine, but the key doesn't engage so the fit spins it until you load it up then it slips. ( of to watch fight club now..but I don't like to talk about it)

[kerny]

Originally Posted by PeterM

( of to watch fight club now..but I don't like to talk about it)

Come on Peter, tell us where the venue is .....

[Nos4r2]

Originally Posted by earthdog1970

But why would it go from a good jet on start up, to water getting very hot and stopping altogether.

Blown powerhead to leg gasket at a guess.

[m chappelow]

Just wondering if its anything to do with the rubber seal / grommet on the riser pipe where it push fits to the power head .

[Locozodiac]

Originally Posted by m chappelow

Just wondering if its anything to do with the rubber seal / grommet on the riser pipe where it push fits to the power head .

Good point. Check all water grommets to see it's condition, could be rotten, dried out, producing water leak somewhere on the water path, impeller housing, water pipe, block.

Happy Boating

[paddlers]

Just a thought but have you tried connecting a hosepipe direct to the pipe that runs into the engine from the impellor and running it to see if it circulates ok ?
If this is going to damage anything I'd appreciate somebody saying so ??

[Locozodiac]

Originally Posted by paddlers

Just a thought but have you tried connecting a hosepipe direct to the pipe that runs into the engine from the impellor and running it to see if it circulates ok ?
If this is going to damage anything I'd appreciate somebody saying so ??

Not that will damage anything, but salt formations, crusts that blocks/lessens best water circulation to disipate heat inside engine won't be removed, will need to be removed mechanically by hand. It's like having artereosclorosis...

Happy Boating

[m chappelow]

If in doubt & you have a decent cordless drill you could always eliminate the waterpump & impeller after assembly by immersing it in a tub of water & rotating the drive shaft to see what the water pressures like or how good it's coming out of the pipe before you join it back to the engine .
(You don't need to rotate the shaft at a really high speed )

If the pump housing or base is badly scored or its perhaps been fitted with a thicker gasket you can loose water pressure from the the impeller top & bottom sealing surfaces & not just at the blade tips
If you use your engine on a shallow sandy beach or in shallow gritty mud a lot you can see the difference in the waterpump scoring to an engine that spends its working life in deep water .

[Davie]

Originally Posted by earthdog1970

no the bottom one is the old one, and yes I think the new one has a brass lining.

Your asking for trouble ahead fitting after market impeller with brass inset. Phone Graham and ask for part number 6h4-44352-00

[earthdog1970]

Well finely got there in the end, put the new impeller in and thermostat and its now putting out a good strong jet,and sticking at the right temperature, so what ever it was it now seems to be OK.