Re: 1990 Merc 100 HP Full throtle bogging of the engine
Scott,<br /><br />It's real easy. Disconnect the hoses from the pump. Should be 3, fuel in, fuel out, and crankcase pres/vac. If there's a 4th, that'll be oil in and you need the -42909A4 kit. <br /><br />On the pump you'll see 4 screws. 2 go all the way through and hold it to the block. As you loosen them you'll work out which ones they are. Remove the pump from the engine and put it on a CLEAN rag on the bench. <br /><br />Remove the 2 remaining screws and carefully take the pump apart, noting the positions of gaskets and diaphrams. The gaskets and diaphrams also have notches on one edge. This lines up with the notches cast into the covers and body of the pump. Inside the body are the valves. The kit has relacement valves, and they may look different to the ones in the pump. Merc changed them a few years ago. Put the new valves in and start reassembling the pump with the new gaskets, springs and diaphrams. I find it easiest to put the front cover on the 2 screws and put it facing up on the bench, then just 'drop' each section onto it. Nip up the screws and refit it to the engine with a new mounting gasket. It's important not to get this one upside down too, it's the other pres/vac for the diaphram. Re-plug the hoses and at this point I put a new filter in as well. Sits between the pump and the first carb. Volia! Done!<br /><br />Chris............
