Is there any way to adjust the fuel/oil mixture on a Challenger 2000 with a 240efi motor? I go through about a gallon of oil for every tank of fuel and I have to replace all 6 spark plugs after 3 tanks of fuel. I run 80 of rope when I pull the kids on the tube because they complain about the smoke and the smell burning their eyes if I run a shorter rope. I never had this problem with my Yamaha jet boat. Any suggestions would be appreciated.
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Oil pump adjustment on 240efi Challenger
- Thread starter mrjimbov
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Dr Honda
Well-Known Member
I just dug though a few of the Merc manuals, and from what I can see, no, there isn't a way to adjust the oil pump. It is controlled by the computer from 120:0 at idle, to 50:1 at full throttle. It also said that the oil tank should have enough oil for 150 gallons of fuel. (sounds like you are burning a lot more than that)
There are a couple things that came up, you may want to check.
1) The system has a "4 psi" check valve. Also, to prime the system, you use compressed air. I'm thinking if that valve is plugged up, it may be force feeding the engine too much oil.
2) The computer will run the engine rich for a "Break-in" mode. You may want to take the boat to a Merc dealer, and have them check to see if it's in that mode for some reason. (they have to hook into the computer)
These are both just guesses. (sorry)
If those aren't the problem... I would say you need a new pump.
There are a couple things that came up, you may want to check.
1) The system has a "4 psi" check valve. Also, to prime the system, you use compressed air. I'm thinking if that valve is plugged up, it may be force feeding the engine too much oil.
2) The computer will run the engine rich for a "Break-in" mode. You may want to take the boat to a Merc dealer, and have them check to see if it's in that mode for some reason. (they have to hook into the computer)
These are both just guesses. (sorry)
If those aren't the problem... I would say you need a new pump.
1) The system has a "4 psi" check valve. Also, to prime the system, you use compressed air. I'm thinking if that valve is plugged up, it may be force feeding the engine too much oil.
Where would I find that valve? And does it say how to remove and clean it?
I hate to take stuff to the dealer because they are sooooooo slow about getting things done and then it costs a fortune!
Where would I find that valve? And does it say how to remove and clean it?
I hate to take stuff to the dealer because they are sooooooo slow about getting things done and then it costs a fortune!
Dr Honda
Well-Known Member
It's in the hose between the oil reservoir and the remote oil tank.
As far as cleaning it... I would recommend kerosene and compressed air. If you use carb cleaner, and there is plastic inside of it... it could destroy it.
I understand about the dealers... but unfortunately, when you need to look at the diagnostics... that's the only way.
If you get a manual for that engine... you may be able to check a few more things, but the book I was looking at didn't give any real tests on the oil system. A summery of the oil section shows the parts, gives a description of their function, and says to replace the pump if there isn't a mechanical issue. (clogged or broken parts)
I'm sure the pump is crazy expensive, and I would rather have the dealer check to make sure that the computer isn't telling the pump to send extra oil before replacing it.
I am no expert but I just got finished rebuilding a 240EFI in a 2000 Speedster and the oil pump is controlled by mechanical linkage and not the computer. If the Challenger of that year is the same then the oil pump can be adjusted by the linkage and it tells you how in the correct engine manual for that year. You can download the correct manual from this forum. Maybe the linkage has come loose and the oil pump is full open and not being properly adjusted.
I can't find a picture I took that shows the oil pump. It is slightly hidden and really can't get a picture of it. I was hoping one of the pictures I took when I disassembled the engine would show it but they do not. If you look in the correct year manual for the engine you can see it.
WAJetboating
Member
Took the words right out of my fingertips {grin}.
The ECU on these pre-2002 240EFI's is very simple. For example, it plays no role in oil injection at all. As you point out, injection ratio is entirely controlled by an arm from the throttle linkage to the oil pump. It is a variable ratio from 0-100% throttle, but that is achieved mechanically.
Likewise, the oil system on this engine is mind-numbingly simple. Oil from the on-engine tank flows down through the pump and into the VST where it is mixed with fuel. That's it. The only active component is the pump.
The oil pump's cam is spring loaded so that if the arm comes off, the pump defaults to "maximum oil" to protect the engine. That sure sounds like what is happening here. I completely agree with the recommendation to confirm the arm is connected on both ends and that the oil pump cam rotates CLOCKWISE when the throttle is ADVANCED. Proper installation requires that the cam be preloaded (partially rotated) before the arm is connected.
Once you have confirmed that the pump cam is rotating properly with the throttle, next confirm that the cam is properly aligned. The manual gives very clear instructions and illustrations on how to do this. It is a little awkward when the VST is still on the engine (the throttle-to-oil linkage is somewhat hidden behind the VST) but it can be seen and can be adjusted. Just be patient and watch things move while someone else changes the throttle and it will become obvious.
Report back!
Good Post - Pictures?
I too have the smoking boat issue as described by the originator of this thread. I found WAJETBOATING's post to be the best at explaining how to resolve this issue. I will be looking at my engine's oil linkage tonight. Do have or know of links to pictures of what I should be looking at? This could be very useful to new-bee like myself.
Thanks!
Thanks!
I too have the smoking boat issue as described by the originator of this thread. I found WAJETBOATING's post to be the best at explaining how to resolve this issue. I will be looking at my engine's oil linkage tonight. Do have or know of links to pictures of what I should be looking at? This could be very useful to new-bee like myself.
Thanks!
Thanks!
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