Suzuki DF140 not going over 4,000 RPM

[jcalagaz]

I have just bought a used SeaPro 21 with a DF140 on it and I have had several times that I have taken the boat out and it will not get over 4,000 RPMs. Usally after 15-20 min the problem will go away and will not happen the rest of the day. However today it took about 30+ minutes of riding and it finally got up to speed on the way back to the ramp. I can tell the problem is about to go away because you feell the whole boat surge forward and then slow back down.

The boat/motor is a 2004 and has about 100 hours. The boat sat unused for about a year so I thought it was a fuel problem, but I have added about 30 gallons of fresh fuel.....

I do not have the owners manual, so it may be as simple as inproper start up procedures, but I do not know.....

I just pump the bulb up turn the key (wait for the buzing to stop and then start it....is that right?

Thanks
Joe

 

[bgbass.1]

Re: Suzuki DF140 not going over 4,000 RPM

if it sat that long you should rebuild carbs and replace waterpump also change lower end oil. sound like carbs are all gunked up

 

[jcalagaz]

Re: Suzuki DF140 not going over 4,000 RPM

I am not sure but I think it is fuel injected so it does not have a carburetor?

 

[hopalong]

Re: Suzuki DF140 not going over 4,000 RPM

Assume you know that water and or bad gas always settles to the bottom of the gas tank. Adding more gas wont stop the bad gas/water on bottom from being sucked thru the fuel line pick up (which is the tube inside of the gas tanks that extends near the bottom of the tank) and onto the fuel filter and pump. Once it is pumped into the carbs it usually will settle into the bowls/passages at the lowest point and continue to give problems.
I would suggest you buy one of the inexpensive manual bulb siphons and insert the inlet gas line down into the very bottom of the tank and siphon about a half gallon out and into an approved container. See if there is water or bad gas there...water will lay on the bottom. If there is you will need to remove all fo the water/bad gas from the tank.
And drain out the gas from the carb bowls and see if there is water or bad gas there. There is a large brass screw on the side of each carb. Besure to attach a neoprene hose or fuel hose to the carbs brass tube outlet so as the end of the hose spills into a small container. See if any water is present. If so you most likely will need to remove and disassemble the carbs, clean, and install a rebuild kit.
If you have fuel injection you would check and clean the fuel passages. See a manual for how to.

 

[jcalagaz]

Re: Suzuki DF140 not going over 4,000 RPM

Thanks I will try that.....Is it typical for the engine to run at 4000 RPMs if it senses water?

It does not "sputter" it just runs at 4000 for a little while and then runs fine. It has only been about 3 weeks since I ran it with no problem. Is it possible for condensation to casue that much water to get in the tank in that amount of time?

Joe

 

[reeldutch]

Re: Suzuki DF140 not going over 4,000 RPM

probbebly you have dirty filters and injectors.

drain the vst tank there is a drainscrew with a pink hose. loosen that screw and drain it out in a glas and look at the fuel.
change the filters high and low pressure.
run the motor with injector cleaner and fuel stabilizer.

hophely it will clean your injectors.
and get rid of your old fuel and instal a new water fuel seperator.

good luck.

 

[hopalong]

Re: Suzuki DF140 not going over 4,000 RPM

Well, these days service stations regularly change the filters at the pumps. BUT you never know when a trip to the gas station might pump some water. This happened to my F150 truck last year. Of course the station paid for the servicelabor charges Ford billed me. Ford pumped out about 2 "gallons" of water out of the two truck tanks and had to remove the EFI fuel logs and injectors.
If you did not "add" any fuel after the outing you had when the motor ran fine it should take much more time to have condensation within the tank. But since you never checked the condition of the gas that was in the tank for over a year, I would suspect there may be some trace of bad (old gas will loose its octane over time) gas in that tank. Bad gas lacks the octane it once had and will cause wn engine not to reach full rpms or for that matter sometimes to hardly run.
I would suggest that you at least get a sample of the gas from the tank bottom and if it seems ok then check the injection system. Get you a manual to perform any fuel test at the injection system.
You can kinda relate the gas issues with a car...meaning if you have bad gas the tank of the car the engine would not run very well, not getting the min. octane to all cylinders. One would look at the fuel in the tank and drain it if bad, change the fuel filters, and clean out the fuel injection system. To see the engine injection and filters you have for the DF140 go to www.brownspoint.com and click onto the "parts info" picture and follow the trail from there.
A trip to a reputable outboard mechanic may help identify the problem.

 

[hopalong]

Re: Suzuki DF140 not going over 4,000 RPM

Also you mention in time it gets up to speed. What is the max rpms that the motor will do and the speed? Assuming it is relative more than 4000 rpms.If not you may have other issues

 

[jcalagaz]

Re: Suzuki DF140 not going over 4,000 RPM

Once it was over the problem the max RPMs is about 5500 and about 35 MPH

4000 RPM and about 18-20MPH and took for ever to get up out of the water....

Thanks
Joe

 

[Bobalex]

Re: Suzuki DF140 not going over 4,000 RPM

I just had a similar problem with a 2 cycle fuel injected 225 hp yamaha. After trying various things I broke down and took it to the shop. $424 later it now runs fine. Motor didn't get much running time before I bought it. They cleaned the vapor seperator and filter and replaced a gasket in the float chamber. Also changed plugs but said that wasn't the problem. Said problem was caused by old gas. The said the best way to avoid proble was to run it regulary. It runs great now.

 

[middleton1]

Re: Suzuki DF140 not going over 4,000 RPM

All of the above is good info. I had almost the exact same experience with my 2000 DF70 (yes, I know its a different engine) and had read on here that spark plugs need to be changed, even if they look fine. I changed the 4 plugs and she ran great!

So, try the cheapest and simplest thing first, then move on to more complicated solutions.