• Welcome to Jetboaters.net!

    We are delighted you have found your way to the best Jet Boaters Forum on the internet! Please consider Signing Up so that you can enjoy all the features and offers on the forum. We have members with boats from all the major manufacturers including Yamaha, Seadoo, Scarab and Chaparral. We don't email you SPAM, and the site is totally non-commercial. So what's to lose? IT IS FREE!

    Membership allows you to ask questions (no matter how mundane), meet up with other jet boaters, see full images (not just thumbnails), browse the member map and qualifies you for members only discounts offered by vendors who run specials for our members only! (It also gets rid of this banner!)

    free hit counter

65u & 66h Oil injection Info


Jet Boat Junkie
Reaction score
North Platte, Nebraska
Boat Make
Boat Model
Boat Length
Use this information at your own risk, I am not wanting to start any pro/con oil injection argument.

Among my many winter projects I have started to tinker with resorting the oil injection on my LX210. I thought I would share some pictures of how the system works for anyone else interested and my future reference. I bought some used oil pumps two from a 66h (boat) and one from a 65u (Waverunner) and decided to take them apart to see what kind of condition they were in and what makes them tick. The pics are from the 65u pump and the 66h pumps were identical with the exception of the cable arm being a little different for a different cable end and the end cover has a nipple for a remote bleed screw instead of the bleed screw on the pump.

I will start with the most useful information for most people, when in idle the pump arm is supposed to be set so that the line on the cable arm lines up with the line on the pump body as shown.

as the arm advances it gets to the point were the dot on the arm lines up with the line on the body at that point the pump is wide open there is no limit to pump plunger travel or increase in oil flow after this point as shown.
should the cable brake or not be hooked up the cable arm is spring loaded clockwise and will turn the internal cam over center to a wide open position and not limit pump plunger stroke after about this point up until the tab on the arm hits the stop on the pump.

I'm not sure how well I can explain how the pump internally works but I will try. Shown is the input drive shaft, a copper thrust washer, the pin that holds the shaft in the pump, and a seal retainer that is unimportant to this description. The driveshaft is driven counter clockwise by the flywheel bolt turning the worm gear on it and in doing so the driveshaft is pushed into the copper thrust washer.

the drive shaft turns the pump plunger, the alignment between the two gears is not fixed the plunger moves in and out to pump. It is pushed out with a spring to fill the pump and pushed in by the cable arm cam twice every revolution to pump. the plunger has a stepped shaft because there is two pump chambers. Pictured is the pump plunger and part of the pump barrel. 20240124_214738.jpg
pictured is the plunger inside the pump barrel with the spring that pushes it out and the cable arm cam. The stroke of the pump is limited by the position of the cable arm cam and what part of the plunger rides on the cam the center tit or the lobes on the outside.


There are no check valves in the pump to direct oil flow, oil flow is directed by port timing between the pump barrel and the pump body. The pump barrel is keyed to the pump plunger the barrel only rotates it dose not move in and out. The barrel is allowed to fill with oil when the inlet ports line up with the ports on the pump at the 3 o'clock position and pumps oil out when the ports line up at the 12 and 6 o'clock positions. For every rotation of the plunger and barrel it fills, turns 90 degrees pumps out the bottom two ports, turns 90 degrees and fills, turns 90 degrees and pumps the top two ports. So each port is port is pumped separately.


The pump barrel has two chambers each chamber has two crossdrilled intake ports and one outlet port that is directed up or down when pumping. also notice the thrust button at the end of the barrel it would be easy to loose. 20240124_214717.jpg

Other pictures for reference

There are also check valves in the lines that are used as pop off valves to keep the oil in the tank from flowing though the pump and filling the engine with oil when it is not running. they should hold about 5psi before they open and should only allow flow one way. Of the nine I had only six were good so I did some destructive investigation on them as well.

If anyone has some old oil injection parts taking up space I still need a remote bleed valve20240125_180216.jpg

and I may be interested in some spares of any part of the system check valves, pumps, cables. I would pay shipping.


Jet Boat Addict
Reaction score
Palm Beach Gardens, FL
Boat Make
Boat Model
FSH Sport
Boat Length
Great write up and interesting info! The remote bleeders are getting harder and harder to find.