New DF250 Surging problem

[kit381]

Hi I am new here!

Just re=power my boat with a new DF250 few days ago, it run all good when I test with the dealer and the mechanic. The problem come after the 1st run, seems the engine begin to surge when rpm reach 4000, I have a video here:

https://youtu.be/M9gmmGs3UHA

at first we think that it is the fuel problem, so I clean my fuel tank, check the filter, check the fuel host, and the problem still exist. after make sure the fuel system has no problem, I try to use a new handheld fuel tank and directly connect the outboard and the problem is still there.

does it mean that the new machine has problem? e.g. the vast filter, low pressure or high pressure pump something like that? but the outboard is brand new! anyone can tell?

[Harper]

Did you also check the fuel lines from the tank to the engine? Make sure they are in tip top shape. I would always replace old fuel lines if I were repowering. Remember that the lines could be deteriorated internally and still LOOK okay. YOu need to examine not only by looking, but by feeling the entire length. That's why I would prefer to just replace them when repowering.

In rereading your post, you say you checked fuel "host" so perhaps you meant fuel hose. In any case if you thoroughly checked everything, then take the motor back to the dealer.

[artdf175]

One more point
You indicate this is 'brand new'
Have you worked through the 10 hour break-in period?
Art

[kit381]

Did you also check the fuel lines from the tank to the engine? Make sure they are in tip top shape. I would always replace old fuel lines if I were repowering. Remember that the lines could be deteriorated internally and still LOOK okay. YOu need to examine not only by looking, but by feeling the entire length. That's why I would prefer to just replace them when repowering.

In rereading your post, you say you checked fuel "host" so perhaps you meant fuel hose. In any case if you thoroughly checked everything, then take the motor back to the dealer.

Thanks Mike, I will try to change those fuel lines to see if it works.

[kit381]

One more point
You indicate this is 'brand new'
Have you worked through the 10 hour break-in period?
Art

not yet, I try to run it at 4000 rpm only, it run even not enough 1 hour totally.

[artdf175]

Be very careful
Follow Break-in instructions

[Moonlighter]

I would say that since you've tried it on a separate portable tank with no change, and you've checked the fuel system and filters, then you should be talking to your dealer to get them involved in figuring out what is not working properly.

[kit381]

I would say that since you've tried it on a separate portable tank with no change, and you've checked the fuel system and filters, then you should be talking to your dealer to get them involved in figuring out what is not working properly.

Ask the dealer to check, and finally they report there are some rubbish inside the low pressure fuel filter, it stuck the fuel flow. don't understand where it come from. Anyway thanks for all the suggestions and I will test it again in the weekend.

[Moonlighter]

Are you running a Racor style water separating fuel filter in your fuel line between the tank and the engine?

If not, then you really must add one to avoid this issue of contaminated fuel getting thru to the engine again. Essential!

If you do already have one, then if not done already, change the filter element again to make sure it is clear of debris. You may have picked up a dirty load of fuel from the gas station.

Good luck, hopefully the problem is found and fixed now!

[kit381]

Are you running a Racor style water separating fuel filter in your fuel line between the tank and the engine?

If not, then you really must add one to avoid this issue of contaminated fuel getting thru to the engine again. Essential!

If you do already have one, then if not done already, change the filter element again to make sure it is clear of debris. You may have picked up a dirty load of fuel from the gas station.

Good luck, hopefully the problem is found and fixed now!

I do have a Racor between tank and engine, but i don't know how the debris can still pass through the Racor.

I think the dirty load is coe from the gas station, as it happened after I fill 300L oil from the station.