Johnson Service Bulletin SB-899 - Fuel Pumps

Sometime ago a change was made to servicing fuel pump assembly #378805 instead of the component parts of fuel pump #377927. Since this change went into effect, there have been dealer comments about the seeming unfairness of replacing the entire pump at $5.50 when only a lower priced detail part required replacement.

First, assembly of the fuel pump is somewhat critical, particularly location and retention, during assembly, of the diaphragm, springs and disc valves. Our experience with engines returned to the factory, as well as with recalled fuel pumps replaced under warranty, indicates that these parts were very frequently improperly assembled in the field. As a result the pump failed to function as intended.

When such failures occur for the customer after initial field servicing, reservicing becomes necessary either at the customer's expense or the dealers. Where the expense of the additional labor is passed on to the customer, his total monetary outlay becomes more than the price of a new fuel pump. Where the dealer absorbs the expense of reservicing, he very probably loses his profit, and the customer's outlay is still very near or equal the price of a new pump, considering the cost of detail parts and original service labor. Servicing fuel pump assembly #378805 eliminates these problems, and is, in the final analysis, an advantage to both the customer and the dealer.

Second, the dealer enjoys the additional advantage of stocking only one part (the fuel pump) as compared to a dozen or more component parts. This releases storage space to parts with a higher rate of disbursement.

Fuel pump #378805 is basically the same as 377927 except 378805 does not include 376161 nipple and screen. Therefore, when replacing a 377927 pump with 378805, it will be necessary to use the 376161 nipple and screen out of the old pump, or use a new one. Which choice is made depends upon the condition of the old nipple and screen.