Originally Posted by meridian
Cost of the Johnson pump?
We did our two engines a number of years ago. At that time I believe the 1" pump was between $400 and $450. The 3/4" pump was about $40 less, IIRC.
There is sufficient clearance to remove and replace the injection pump oil drain plug above the Johnson pump even with the Johnson pump mounted as ours are. That's not a problem at all. The issue is catching the oil.
The system I came up with works great for that with nary a drop spilled so I have not had any reason to cant the Johnson pump. But doing so will provide a bit more room if you think you need it.
A number of people on the GB owners forum have tried all manner of ways to make it easier to change the injection pump oil with the Johnson pump below it. Different fittings and so forth. To date nobody has been able to come up with a system that works given the lack of clearance even with the pump canted.
Also the metal the injection pump body is made of is very soft. So it is extremely easy to strip the threads in the drain hole. For that reason it is very important to always use a new soft washer when installing the drain plug and to be pretty conservative when tightening it. We have a stock of soft aluminum washers we get from our diesel shop for this purpose.
It's not that big of a deal actually. Some people even simply let the lube oil come down onto the pump body and catch it underneath and then wipe the pump down with a rag.
Regardless, the slight inconvenience to changing the injection pump oil is more than made up for by the elimination of the failure-prone Lehman drive coupler.
I should add that there is no issue with the Jabsco impeller pump itself that is used on the original FL 120's raw water system. They are easily overhauled and brand new ones are still available, or they were last time I checked. It's the Lehman drive coupler that powers the Jabsco pump that you want to get rid of.