1999 Yamaha 4AC Longshaft

[ryanabigail]

looking for advice on the following outboard - 1999 Yamaha 4Hp model - 4AC Longshaft, i have been having a problem with the water flow through the engine, I changed the impellor about a year ago and thought the engine was fine as it started and ran with water coming out of the 'tell tale' hole. I never used it on the boat, however i have nearly finished a refurb of the boat and tried the outboard, it started and ran fine with water again coming out of the 'tell tale' though perhaps not as fast a flow as it used to have, however a the engine warmed up the flow slowed to a trickle and then steam, i stopped the engine. This had taken about 1 minute. I let it cool down and tried it again with the same result. I stripped the leg and cleaned the impellor and housing and put it all back together, the rubber impellor is still as new as it has not been used. When stripped i noticed the fit of the drive shaft through the outer plastic impellor housing was not very tight. I put the leg back together but still got the same result, water pumping through slowly then dropping off and turning to steam as the motor warmed up. I ran a hose through the tell tale and water came out of the tube that feeds from the impellor, i also ran the hose through the tube from the impellor and this came out of the tell tale ok. <br /><br />Is it possible that the loose fit of the drive shaft through the impellor housing is causing a loss of pressure in the water system or is there another possible cause? <br />Any advice would be greatly appreciated.