Suzuki DF30A bogging down

[dankboyz3]

Have a DF30A about 2 years old with about 200 hours on it. Was going about 3/4 throttle planed out for about 5 minutes, then came to a stop and motor shut off. Started back up would only go real slow real rough, then after a couple minutes got back up to speed but would bogged down going fast and slow with the throttle at same position. Any suggestions greatly appreciated, just emptied fuel filter, gas line, and gas tank, added new gas with fuel treatment. still need to take out and run, idled fine

thanks
Erik

[gordonm1]

i interpret what you wrote as you had problems, made some changes, and need to get back out and test again. i think you made good changes as it sounded like you had old fuel or water in fuel issues.

based on that my only suggestion is don't get too far from the boat launch until you have more confidence in your engine if it's the only one on the boat.

[Hoosmatroos]

There can be left some water (if that's the problem) in the VST. When you drain the VST than you drain some left water out there.

For carb motors I often open the drain screw on the carb bowl and use some fresh fuel to rinse the line and bowl from water. Catch the pushed out fuel in a glass jar and see if there was any water in there.

[dankboyz3]

Tried all that replaced fuel line, fittings, primer bulb, new water fuel separator, primer bulb will get and stay hard when not connected to motor. Need to keep pumping when connected to motor, otherwise will run out of fuel. Any help appreciated!!
Thanks
Erik

[TxAg66]

.... Need to keep pumping when connected to motor, otherwise will run out of fuel. ...

If you need to keep pumping the primer bulb to keep it running, wouldn't that suggest a leak somewhere between the tank & the engine?

[Solarman]

Sounds like a fuel pump problem. If you have to keep pumping bulb, or the air leak would be between the bulb and fuel pump. But, pumping bulb (motor off) should show where fuel is leaking?

Good luck.

[gordonm1]

I am a total amateur at boat mechanics but when my 15hp needed the bulb pumped it was a restriction in one of the fuel line fittings. the fitting at the motor cost so much to replace i made the connection permanent with a barbed pipe fitting. no more restriction.

[dankboyz3]

Ran today would still bog down when you get out of idle speed and try to speed up, finally have up and took to shop to get fixed, and get 200hr maintenance and new water pump. Couldn’t find any fuel leak inside motor, but fuel filter reservoir inside motor only 3/4 full unless pumped primer to keep it full, starting to think fuel pump, will find out Monday.
Thanks for the help
Erik

[dankboyz3]

Took to shop ended up being the water pump was bad so was bogging down to protect itself, runs perfect now

[Ollie366]

dankboy
I'm having a similar with my '15 DF30ATL. Runs like it has a fuel problem - ran at constant 2650 RPM and nice a smooth for a mile or so, then tried to rev up to 5000, holds for a few secs,but then drops back and runs really rough. The more throttle I give it,m the worse it runs. My first filter - the one just before the fuel pump - is about 3/4 full and the bulb isn't hard. Pumping the bulb while it's running poorly makes no difference. It's a new bulb since the original one would not pass fuel. Bypassed my Racor, just in case, but no difference.

Hard to imagine it's a water pump but that's what you found? My telltale stream is really strong. Did your mechanic find anything else that might be related? Fuel injector issue?

Any info/ideas will be greatly appreciated. The motor has been trouble-free but now, since I'm about to sell the boat, it's acting up!

[Ollie366]

Turned out to be the in-line filter between the VST and the high pressure pump was plugged. Bypassed it and it ran like new. New filter is on order. I hope this helps someone else.

[Moonlighter]

Turned out to be the in-line filter between the VST and the high pressure pump was plugged. Bypassed it and it ran like new. New filter is on order. I hope this helps someone else.

Ollie, it is an often overlooked thing on smaller motors, but it is highly recommended to put a water separating fuel filter between the fuel tank and the engine. You just found out why!

Usually one of those Racor type ones is the go, with the clear bowl so you can see any debris or water. We change the filter element at our annual service.

As you have discovered, any efi engine does not run well with dirty or contaminated fuel, regardless of horsepower. We fitted such filter to our small boat with Suzuki DF40a when we had the engine installed.

[2014DF25ARS]

As I interpret his post, Ollie336 DOES have a Racor filter, as do I (based on Moonlighter's advice!)

My DF25A is doing the same thing described in both posts above, at about 170 hrs. After 3 years of no problems, I was on the river a couple weeks ago and ran for 20-30 mins at about 2/3 throttle, then I stopped to look around. When I started up again, the motor wouldn't run above about 1500 RPM. It felt the same as when I forget to attach the fuel line to my tank - like a fuel supply problem. I replaced the primer bulb and my Racor filter, but neither made any difference. Motor will idle in gear all day long. Makes no difference when I pump the primer while running. It's still under warranty, so I took it to a dealer for warranty service. I would like to find out it's the same filter. He said it would be about 2 weeks before he could get to it, so I'm still waiting to find out. I need to look up this post-VST filter! I hope he tells me it's the same problem, because that sounds fairly easy to fix.

[2014DF25ARS]

Well, this internet thing has proven itself valuable once again! I had the same problem described by others in this thread. I have a DF25A motor with 170 hrs, about 3 years old with a 6-year warranty. A month ago I spent the day zipping around the lake as usual, without any problem. The following weekend I went out on the local river and spent about 20-30 minutes running at about 1/2-2/3 throttle. I stopped to look around, and started back up again as usual. After about 10 seconds, the motor bogged down to a fast idle. When I tried going any faster, it just felt like it was starving for fuel, and wouldn't go. I drained the fuel out of the low-pressure internal water-separating filter, thinking maybe there was some water in there. (I do have a Racor filter between my portable fuel tank and the engine, so I don't expect water in the engine.) Tried running off my second fuel tank with no difference. Never could get it going, so we limped home in gear at idle speed; took about 30 minutes to return to the dock.

The next day I replaced my primer bulb (again), and drained and then replaced the Racor filter. When I drained it, I did find about 10% water in the bowl, and it was about the age to need replaced anyway. Took the boat back out hoping for the best, but same thing - it ran for about 10-20 seconds and then bogged down to idle, as though starved for fuel. It felt the same to me as it does when I forget to attach the fuel line to my tank when taking off. I also tried pumping the primer bulb while running, but that made no difference - which surprised me a bit.

The next week I took it to a dealer for first-time warranty service. Guy told me it would be a couple weeks before he could look at it. During those two weeks I found this thread where two people described similar symptoms and fixed the problem by replacing the high-pressure (in-line) fuel filter - between the Vapor Separator and the high-pressure fuel pump. I bought a couple of these filters and yesterday went to the dealer to check the status of my motor. 2 1/2 weeks after leaving the boat with them. They hadn't got to me yet - said it would be sometime this next week. I have no problem with that, but I had a group of kids at my house this weekend who wanted to go boating. So I took my boat back to my house and changed the in-line fuel filter (about 20 minutes and $20), and the motor ran like a champ the rest of the weekend. So for the time being, I'm convinced the fuel filter was the problem.

When I left my boat for service, the dealer said it sounded as though something was making my motor go into limp mode. Honestly, that hadn't occurred to me, as it felt to me as though just starved for fuel. But I think he is probably right. I have a Suzuki 4" NMEA gauge on my motor, so I would expect it to show me some message if some condition put the motor in limp mode... He also told me they've seen several Suzuki motors where the high-pressure pump has burned out. He said the pump is cooled by fuel flow, and he knows one guy who always ran his motor out of fuel at the end of every outing, and burned out the pump. I use two 3-gallon tanks in my little boat, and my standard practice is to run until the first tank runs empty, then switch tanks and head home. So I DO run my motor "dry" on every third or fourth outing, though I usually stop to switch tanks at the first sputter.

But given what I've now seen, I wonder if there's not an input pressure sensor on the high-pressure pump that puts the engine in limp mode when the input pressure is too low, to protect the high-pressure pump. If so, I can imagine that when that in-line filter gets clogged to the point where the input pressure to the high-pressure pump is too low, then the engine always runs in limp mode. If this is true, then my main disappointment is that my gauge didn't give me some indication of a problem.