new to forum. power issue df 140

[plumber1]

Owned a df70 for 18 years change the oil, water pump, fuel filter at interval... worked perfect forever. Trade Up to a brand new boat with a df140 2019. Getting ready to run its second full year. Stored in Wisconsin cold weather with a full tank of Premium no ethanol fuel and stabilizer. I just went out yesterday, took the boat out started right off run smooth as silk but cannot get over 4500 RPM or 27 miles an hour. This is perfect setup that was set up and experimented with last year to achieve 6100 RPMs at 42 miles an hour with a Michigan wheel 14 by 19. Throttle all the way down just doesn't sound high pitched enough but again the motor run smooth as silk. Fuel separator? Fuel filter? Again I don't have enough hours to Warrant either the above and I use high quality no ethanol fuel from a high-volume service station. Thoughts?

[briscoe]

Sounds like fuel issue. Check water separator.

[plumber1]

I'm a plumber and should know this but I do not, can the fuel water separator canister be cleaned and not replaced as I am many miles from parts.

[Murray]

I agree with Briscoe, if it ran fine before winter and not fine after sitting all winter then one would think you have a fuel issue.

When you added stabilizer last fall, did you run the engine, not idling in the driveway but a good run on the lake? Reason I’m asking is I bought a boat that sat for two years that was winterized, the fuel in the tank was a light amber colour while the fuel in the VST was almost black. The shop obviously didn’t run the engine long enough to distribute the fuel stabilizer throughout the entire system. At the bottom of the VST you should have a drain screw, collect a cup of fuel and evaluate the fuel. Fresh fuel should be clear, old state fuel will have a amber colour. Some water separators have a drain screw at the bottom, some are are clear, can you see a separation of liquids? Drain a cup or so of fuel and see if you have water in the fuel, water is heavier than fuel so water will collect at the bottom and be the first to get sucked into the engine. If you have moisture as opposed to water try running some gas line antifreeze through the system. You can also remove the water separator filter, reinstall the bowl and try running the engine to see if your issue clears up. When running, watch the inline fuel filter looking for bubbles, I’m thinking one of your fuel lines contracted slightly and perhaps you don’t have a good seal allowing air to get sucked in where it shouldn’t be?

[plumber1]

When I checked the fuel separator, and this is the first motor I've had this large enough to have one it wasn't even finger tight so I'm guessing it may have contracted and wasn't a good seal, drained it into a glass jar it looked like fuel with nothing in it obnoxious anyway, I screwed it back on went out gained 1000 RPMs and 5 miles an hour but still not where I was I'm thinking perhaps I just need to blow the fuel out of this thing and hope that it is a fuel issue that will clear?

[Murray]

If your fuel separator was loose I’d be checking all the other fuel lines and associated clamps. Running some gas line antifreeze can’t hurt, follow the instructions as to how much to add, it’s cheap insurance and will rule out moisture in the fuel.

[briscoe]

Plumber, for sure you ruled out the separator. I had one that formed rust around the very top and was giving my engine a fit. The loose filter would explain why it wasn't getting enough fuel. I would have expected it to cause the fuel bulb to be soft too. Have a good season. About that time

[briscoe]

I realize now that you're questioning the top end of WOT (Wide Open Throttle) rpm's. That is determined by your prop. WOT should be 6200 rpm's on a DF140. Even though OB's are designed to run WOT, most want to get to 5800 - 6000. For you, 5500 means your have to long of a twist. Let's say your running a 22, you may need an 18 or 19. Lower twist better hole shot, higher rpm for WOT. I would look at the home page under Prop selection. There is a great article on discovering the proper prop for your boat.

[Moonlighter]

When you re-attach the fuel separator element, did you moisten the rubber seal with some engine oil?

[plumber1]

Okay fellows I'm back from a week of medical leave. The df140 when I stored it in November was at 6100 RPMs at 45 miles an hour perfect for my boat I could trim it all the way up and not break loose ....wouldn't lose it in the turns... perfect setup. The problem is I only am getting around 4500 RPMs again I changed the spark plugs... fuel separator ...drained the vft, and it still runs smooth as silk starts right up but it's like I'm not getting anything. I checked the throttle cables everything is double knutted and idling and shifting where it's supposed to... nothing is changed in the set up since it was perfect last fall. So I'm guessing it must be a fuel issue or an injector or coil pack?.. upon taking the hood and shroud off there is absolutely no evidence of intrusion by a rodent a gremlin or otherwise. So before I pay through the nose at the dealer if anybody has any light to shine on this it would be appreciated. I appreciate the responses and respect all of you guys but it doesn't appear that all of the respondents have read the entire story. the boat is set up and propped correctly, Motors hung properly (height)... again when I put it away last year it was perfect so what would cause a motor to run completely smooth but 2500 RPMs off?

[catacom225]

Have you checked the primer bulb! your fuel tank may not be venting properly. Get hold of a portable tank and run it that way you can eliminate that side of the equation

[plumber1]

I do have a portable fuel tank I'm not sure how to clip it onto the 140 because unlike all my other Motors that had a thumb clip and a push pin this is in a 2in flexible conduit. But as I was going along today wide open I could squeeze the bulb it will with my 60 year old arthritic hands it wasn't hard but it didn't seem to increase the RPMs when I was squeezing it

[Handsomerob1980]

So it doesn't bog down or misfire when you put the throttle hard down? the only symptom is that it doesn't rev past 4500 RPM? You say it runs smooth just doesn't sound like it reaches peak RPM. I'm not overly familiar with this system but it sounds like something electronically may be limiting the RPM, a sensor or something not seeing what it wants. lack of fuel, air, or spark would have an effect on the engine, it would not run smooth as silk lacking any of that. so unless your boat has gained a substantial amount of weight over the winter or the prop as been damaged I would suggest getting it to the dealer and having them check what the sensors are doing through the throttle range.

[catacom225]

Plumber are you sure its 4500rpm and not 3500, as the latter would indicate its in error or limp mode as Handsome suggests Unlikely bad fuel if it runs fine up to 4500 but still could be fuel related.

[Moonlighter]

There engines will run SURPRISINGLY smoothly with a bad spark plug.

Except they wont rev out.

Just say’in....