Over heating Donzi Sweet Sixteen

[sctiberio]

:confused: I've had trouble with my 91 Donze overheating. I've replaced the pump, the theromostat, the risers and headers and every water hose on the boat, including in the gimbal housing. I've narrowed the problem to inadequate water delivery from the pump. Water delivery is adequate when under pressure, (i.e. from a hose), but almost non-existant when the outdrive is sitting in a tub of water. At this point i have to believe that the problem is on the suction side of the pump in the outdrive. Maby a cracked or loose water tube or the manifold it attaches to. Possibly freeze damage. Before I remove the outdrive and split the case, can anybody think of any other possibilities?

[sctiberio]

Yes, It's A Cobra. 5 Liter Ford 302 V8

[sctiberio]

it was in salt water with the previous owner.

[glashole]

have you replaced the impellor in the drive yet?

[sctiberio]

I've Replaced The Impeller And The Plate Underneath It. There Was A Fair Amount Of Sand/mud/grit Around The Back Side Of The Plate Where The Drive Shaft Comes Through, So I Cleaned It Well. There Is A Small Grove Behind The Plate That Is Supposed To Prevent Vapor Lock And Assist Priming. It Was Cloged With Sand, But It Is Clear Now.