Yanmar Raw Water pump Oday 25
- Thread starter Captain25
- Start date
Removing the entire pump is quite simple; I just did this recently to replace my old one, which was leaking. However, if you replace the cover plate screws with stainless hex head screws then you can easily get to the one difficult screw that's blocked by crankshaft pulley using a small (7mm, if I recall) wrench. So I always replace my impeller with the pump in place.
Until you replace those screws with hex heads, you could either just remove the entire pump or, to remove that one tricky screw, use a small 90-degree ratcheting screwdriver like one of these: http://www.mcmaster.com/#5695a1/=sjkqoj
When you change the impeller be sure to have a new paper gasket. I find that even with a new paper gasket the cover plate still can weep a bit of water, so I now just routinely coat both sides of the gasket with Permatex gasket sealer before installing it.
Another tip that might be helpful is that I use a small wire tie to help keep the impeller vanes compressed while I install it into the pump. This is a very small pump with a tiny impeller and I find the wire tie to help with the installation.
These pumps a prone to developing leaks, so keep an eye on sea water dripping from the weep hole on the bottom of the pump. If it does leak the salt water can damage the oil lines, which could potentially cause a catastrophic engine failure if they break and empty the engine of its oil while running. Carefully inspecting all three oil lines regularly is a good thing to do, by the way, since these are known failure points on this engine. Also, the salt can play havoc with the motor mount that is near the pump.
The 1GM is a great little engine but the three common problems with it are: (1) the leak-prone raw water pump; (2) the three steel oil lines that can and do rust out; and (3) The exhaust elbow, which can deteriorate in such a way that the raw cooling water can get into the cylinder head. Problems 1 and 2 are often related, with a leaking pump leading to the rusting oil lines. Aside from the cost, swapping out the pump can be done easily in 10 minutes. The oil lines are not especially difficult, either, though you do need to remove a few things to get at one of them. As for the elbow, it's simple enough to remove and I'd suggest pulling it periodically--yearly maybe, depending on what shape it was in last time you inspected it.
This may go a bit beyond what you asked for, but I hope you find it helpful. Report back on your experiences with the pump.
This rocks! I am going through this exact problem. I let it go too long. It it was a problem well before I bought the boat, though. The bolts that hold the whole water pump assembly had rusted out so badly that one sheared off while I was removing it. Now have the challenge of extracting 3/4s of that bolt that is stuck in the engine block, rusted. Have already replaced the oil lines, that yes, ruptured pier side during dewinterizarion start ups.
Changed out the rubber fuel hoses to and from the engine over the winter... Another 'deferred maintenance' item that had probably gone three years without being done. They had become as hard a plastic around the brass nozzles.
Changed out the rubber fuel hoses to and from the engine over the winter... Another 'deferred maintenance' item that had probably gone three years without being done. They had become as hard a plastic around the brass nozzles.
