quick question

[davey g]

hi all my pal has just purchased a merc 50hp blueband and he has changed the impeller plus the housing and the bowl when in neutral the water stream is great also in gear with no revs its great but soon as you accelerate it dies rite down to very little does anyone know what else could be causing this any help would be appriciated thanks dave.

[Charlton]

is he testing it in a tank, with a hose attachment or out at sea.

[davey g]

is he testing it in a tank, with a hose attachment or out at sea.

hi he tested it in a tank and at sea i have 1 of these engines my self and it pumps great when in gear and moving quick

[braine]

Looks like the impeller blades are distorting under load. The impeller may be put in wrong way round especially if there is a slight bend to the vanes. The bend goes towards the flow so that on acceleration, the vanes straighten out to increase the diameter so giving a greater flow. If the impeller is installed the wrong way round, the vanes bend further under load so increasing the distance between the edge of the blade and the bowl, decreasing the flow.
Seems like a canny explanation to me.

[Charlton]

go along with Bill on that, defnately sounds as if he has put impeller in wrong way round. If he had been using a hose attachment he could have simply not had enough water flow, but if tested in tank/sea plenty water.