Rebuilding a Mikuni Fuel Pump

[C5Engineer 1170]

It is recommended this task be completed once a year. The only tools you will need is a phillips screwdriver and a dab of grease. Task completion is approx 30 minutes tops.

First purchase the rebuild kit California Power Systems part #6909

I made a mark with a marker all the way down the side of my pump so there would be no question how the three pieces went back together when I was done.

Next take out the screws holding the two halves of your pump together. I recommend only pulling one half at time apart. Remove the old parts and install the new parts in the EXACT order they were in there before. The top and bottom use two different shaped gaskets.

In the middle are two little plastic discs with a rubber plug holding them in. They are a pain to get the old plugs out. Put a dab of grease on the new plugs before trying to shove them back through the hole or it'll never go.

Make sure everything is lined back up before putting the halves back together. There is a total of 6 layers of stuff the screws have to go through.

Tighten the screws in a cross type pattern like you would do the lugnuts on a car so that it tightens on the gaskets evenly.

I also recommend replacing your pulse line at the time as you do your pump. Make sure you use actual pulse line. It is stiffer than regular fuel line. The walls of regular fuel line will bulge making you lose the critical pulse that runs the pump. You can also get pulse line from CPS Part # 7606. I had my pulse line break off right at the bottom of my pump on my Powered Parachute because it was old and had become brittle. My engine quit right afterwards. Thank goodness it happened during my warm up.

Feel Free to PM me if you have any questions

Joey

Rebuild Kit part number

[horsepower 24]

It is recommended this task be completed once a year. The only tools you will need is a phillips screwdriver and a dab of grease. Task completion is approx 30 minutes tops.

First purchase the rebuild kit California Power Systems part #6909

I made a mark with a marker all the way down the side of my pump so there would be no question how the three pieces went back together when I was done.

Next take out the screws holding the two halves of your pump together. I recommend only pulling one half at time apart. Remove the old parts and install the new parts in the EXACT order they were in there before. The top and bottom use two different shaped gaskets.

In the middle are two little plastic discs with a rubber plug holding them in. They are a pain to get the old plugs out. Put a dab of grease on the new plugs before trying to shove them back through the hole or it'll never go.

Make sure everything is lined back up before putting the halves back together. There is a total of 6 layers of stuff the screws have to go through.

Tighten the screws in a cross type pattern like you would do the lugnuts on a car so that it tightens on the gaskets evenly.

I also recommend replacing your pulse line at the time as you do your pump. Make sure you use actual pulse line. It is stiffer than regular fuel line. The walls of regular fuel line will bulge making you lose the critical pulse that runs the pump. You can also get pulse line from CPS Part # 7606. I had my pulse line break off right at the bottom of my pump on my Powered Parachute because it was old and had become brittle. My engine quit right afterwards. Thank goodness it happened during my warm up.

Feel Free to PM me if you have any questions

Joey

Rebuild Kit part number

Nice article Joey, I was actually planning on rebuilding my pump before installing it so this should help.I have a question on fuel line size.I have 1/4 inch coming off of each tank that goes to a header tank behind the rear seat, then 1/4 inch running up to the pump mounted on the firewall as that is what Rotax say to use.Is this large enough or should I be using 5/16. Im a boat mechanic so Im comparing to outboard motors, example a 50 HP Johnson outboard requires a 5/16 fuel line.Probably a dumb comparison but the older I get the more questions I seem to ask.Thanks Randy

[C5Engineer 1170]

Nice article Joey, I was actually planning on rebuilding my pump before installing it so this should help.I have a question on fuel line size.I have 1/4 inch coming off of each tank that goes to a header tank behind the rear seat, then 1/4 inch running up to the pump mounted on the firewall as that is what Rotax say to use.Is this large enough or should I be using 5/16. Im a boat mechanic so Im comparing to outboard motors, example a 50 HP Johnson outboard requires a 5/16 fuel line.Probably a dumb comparison but the older I get the more questions I seem to ask.Thanks Randy

Everything Rotax I have ever worked with was 1/4" all the way to the carbs

[akflyer 1427]

Mine is 5/16" from wing tanks to the gascolator on the firewall, then 1/4" out to fuel pumps and carbs. My brothers old KF II was 1/4" the whole way.