C
craig
We have a 1987 hunter 34 with a yanmar 3gm diesel.I have owned this model for three sailing seasons and just put our boat in for number 4. At the end of last yr, on the hard the raw water system would not take my antifreeze without some persuasion. When the boat was dropped in on friday I had more problems with this. The exhaust sounds hollow and like a muffler blown out vs the typical muffled sound and water coming out the back. Our exhaust water has never been all that powerful but adequate and the motor has never overheated. Anyway this needed to be looked at and I was going to fix it. This is for the novice, copy this off and leave it on your 34 hunter because it may happen to you away from the marina and this simple guide will help you thru the process.1 set the hook if you can, turn off the power and shut the raw water intake by the stuffing box.2 you should have probably two extra impellers and gaskets on board.3 you will need sockets and a screw driver. not too sure on the socket size so IN ADVANCE make sure you have the proper size. a cresent wrench will work.4 as you are kneeling looking at the engine look on the left side at the small belt. the pully it attaches too is where the impeller is. it is behind the pully.5 remove the two hose clamps that attach to this pully.make sure you have a container below as a cup or two of water will come out. no big pressure thing though. take the hoses off and let them drain into the container. after a minute or two dump the container out to avoid a mess. inspect the two clamps and replace if necessary. one of mine was pretty rusty so i replaced it.6 remove two long bolts and the entire pully and impeller system will come off.7 on the back, there are six scews. some of mine, the head from the phillips screw driver were stripped so i replaced all of them.they are metric size. remove the screws,and gently remove the cover. a regular screw driver may be required to help loosen the cover . inside you will see your six vane impeller. three of my vanes were gone and the others were cracked. i used a screw drive to gently pry the impeller out. there was no special clip holding it in. you do have to line up the slot to put back in and note which way the vanes are bent. if you are not sure, just touch your ignition to see which way the engine turns then insert so the vanes drag behind. our engine turns clockwise. i put alittle vasoline in the impeller holder to help lubricate. i then cleaned the cover of the old gasket with a razor blade and reinstalled everything.8 remember to open the raw water intake. start the engine, look for leaks and that should be about it. this whole process should take about one half hour once you have done it. along with replacing filters, this is a very important item we, not the marina should know how to fix. good luck. craig4