got my checkmate with the low hour 1989 225 and just wondering about taking off the gearcase bearing housing that needs to have the o-rings replaced as yearly maintence do i need a special tool as the manual talks about a cover nut tool ,also the manual says to use hypoid gearbox oil no mention of synthetic or a performance gear oil what is the best oil to use in the lower unit.did a comp test top 2 were 125.. middle 2 were 135..lower 2 were 125.. i did it cold with the throttles closed. sound s ok..what lbs should the water pressure read on the gauge. should i replace the fuel connector with a new solid piece of hose. thanks guys