T&T: Problem with injector pump (I think) - solution

[Bob McLeran]

Just wanted to update the list on the problem with the engine not
starting due to fuel not flowing from the injector pump into the 
injector lines (the lines leading to the injectors).

The last time I wrote the list, on December 19th, I had talked with 
Jerry at American Diesel and had been advised to trouble-shoot the 
problem with the injector pump in this sequence:
- make sure the stop lever is in the correct position (full aft) to
allow fuel flow (it was);
- remove the fuel return line from the side of the injector and try to
start the engine - fuel should flow out of the adapter which is located
between the return line and the injector pump housing (it didn't);
- remove the adapter and see if fuel flows out of the resulting hole
when the engine is cranked (it did - big time);
- use compressed air or WD-40 to try to clear the blocked orifice (a
very small pin hole) at the hose end of the adapter;
- try to start the engine;
- call back.

I've used the term "pin hole" to describe the hole, but actually it is 
so small as to be barely visible.

Jerry explained that with the orifice blocked, too much pressure builds
up in the injector pump and it doesn't work! He said that others with
this problem were able to get their engines started after clearning the
pin hole opening.

A listee suggested using brake cleaning fluid to try to clean/loosen 
whatever might be blocking the orifice or valve inside the adapter, so I 
placed the adapter in a glass jar and covered it with brake cleaning 
fluid. It sat for four days, and then I dumped out the solution (it had 
turned slightly pinkish, either from diesel in the valve or from paint 
on the adapter), shook out the fluid inside of the adapter as best I 
could, and then added more brake cleaning fluid to the jar - enough to 
more than cover the adapter.

A week and a half later (after Christmas in Salt Lake City) my 
son-in-law brought his portable air compressor to my house. We used it 
to blow air through the adapter in reverse of how the diesel fuel would 
flow, and later blew air into the "front" end of the adapter. When I put 
my thumb over the "back" end of the adapter (the part that fastens onto 
the return line) and the end of the air hose directly over the "front" 
end, I could feel a slight pressure build up.

Today I took the adapter to Sanderling, reconnected the fuel lines at 
the Racor filter (I had placed a Walbro fuel pump in-line), and then 
replaced the adapter in the side of the injector pump housing. Gave the 
manual pump lever a two minute workout to get fuel into the injector 
pump (hopefully), turned on the ignition key and pressed the start 
button. After turning over for about five seconds, the engine sputtered 
and then started. It ran smoothly for 10-15 minutes before I shut it 
down. It restarted without a problem.

I don't know what caused the adapter to get plugged, but when it was 
plugged, the engine wouldn't start. With it unplugged, it started.

Some things to keep in mind with the Ford-Lehman 135/90. The injector 
pump is self-purging - there are no bleed screws. There is a procedure 
for bleeding air from the injector pump outlined in the engine manual in 
case there is a lot of air in the fuel system; basically, loosen the 
nuts on the four lines at the top of the pump housing leading to the 
injectors serially from front to back, while working the manual pump 
lever until fuel flows out of the base of the nut, then move to the next 
line, repeat until you've worked through all six or four lines. When 
your troubleshooting fails, call American Diesel at 804-435-3107.

Hope this might save someone some time and head scratching down the line.

<><><><><><><><><><><><><><>Mozilla Thunderbird<><><><><><><><><><><><>
Bob McLeran and Judy Young                       Manatee Cove Marina
M/V Sanderling                                   Patrick Air Force Base
Hampton 35 Trawler