DF 2.5 questions

[johnkimura]

I bought a small trimaran sailboat, a Multi23, and it came with a used 2009 Suzuki DF2.5 outboard with the Walbro LMJ carburetor.

It was always easy to start, and run at half or full throttle, but it would die easily at idle, unless I played with the choke. And it always needed the choke to restart it, even when warm.

I first put in a new spark plug. And that helped a little. Then I see the discussions about everyone have problems and trying bigger jets and so I ordered them online from Brown's Point Marine service.

Suzuki Outboard DF 2.5 Fig. 5 - Carburetor

I ended up ordering the following:

3-6 09491-66005 ▪ Main Jet #66
15-3 09492-34004 ▪ Pilot Jet #34
2-2 13236-97J20 ▪ Main Nozzle

Plus the necessary gaskets.

The order arrived in about a week and I just got it all installed and put back together.

The engine now starts right up, and after a few minutes of warm up, I'm able to push the choke off and it just sits there happily idling. The idle set screw is just barely opening up the throttle valve. The manual says idle is 1900 RPM +/- 100 rpm. I don't have a way to measure it. But my ear says it's close.

I can even engage it into gear at idle and it doesn't die. If I slowly increase the throttle, the engine rev's nicely, but if I suddenly open it up at idle, it dies. For now I can live with that.

It was a straight forward project. Here is what I learned. First, take pictures with your digital camera/cell phone of every step before you take things apart. Just in case you don't remember what goes where later.

The carburetor diagram from the Browns Point Suzuki site is correct. The one from the Walbro site doesn't match the carburetor on my engine.

It was easy to remove the carb from the engine. Just release the choke link at the carb, and unscrew the fitting holding the end of the throttle cable.

The two bolts holding the air intake box and the carb to the engine comes off with a 8mm socket with a small extension.

The fuel line easily came off as did the crankcase ventilation tube. The carb will leak gas when you remove it. Be prepared with a large rag/towel or something to catch the gas in.

The 10mm bolt, at the bottom of the carb, which accesses the main jet and main nozzle easily came off . A 7/32" slotted screwdriver bit worked unscrewing the main jet. And the main nozzle sits on top of the main jet and just fell out.

It was harder to get to the pilot jet. To take the top of the carb off I had to remove the choke plate and choke shaft. Then the four screws holding the top came off.

I thought that I'd have to remove the throttle valve, but I didn't have to. At first I didn't know that and I found that the throttle valve does not come out easily. It's brass, soft with a special beveled edge. In addition, the screw that holds it on has some special dry threadlock so it doesn't vibrate loose and get sucked into the engine cylinder. I ended up using Loctite blue threadlocker to put the screw back in. The loctite should be gas resistant when cured.

The pilot jet sits under a chrome plated screw. Take the screw out and you'll see the pilot jet about an inch down the hole.

A regular screwdriver will NOT get pilot jet out. I ended up buying a metric screwdriver that is 0.8mm thick, 4mm wide and 100mm long (Wera 05032003002) and it was a perfect fit. I have a very good tool store nearby in Seattle ($9.29 @ Hardwicks). The Amazon one below is the exact same tool.

Amazon.com: Wera 05032003002 Kraftform Stainless 3335 Stainless Steel Slotted Screwdriver, Lasertip, 4mm Head, 4" Blade Length: Industrial & Scientific

Once the jets were out, I cleaned everything in carb cleaner and made sure to spray all of the orifices well. I was surprised how much gunk came out of the carb, even though it looked clean.

I used all new gaskets. I had to cut out the old carb bowl gasket and cut off the one on the bottom of the bowl.

I reassembled it all, using loctite on the choke and throttle valve screws. To speed curing of the loctite, I heated the carb with a heat lamp until it was hot to the touch.

Reinstalling it was a snap. Adjusted the throttle cable so there was no tension when the throttle was off, and just barely turned the throttle idle screw to open the throttle valve. I put the outboard back on the boat, then turned the fuel on and opened the gas tank vent. Choke out and it started on the first pull!!!

So far so good. I'll get the boat out and motor around for a while. Then I'll pull the spark plug and see what it looks like. It should be a good indicator of what my fuel/air mix is doing. I may put the #64 original main jet back in if I don't like the response going instantly to full throttle.

As others have speculated, I think Suzuki tuned the engine to run lean so it would pass emission standards. But the engine doesn't like it, especially at low rpm's. So I think the new jets have helped. Or maybe it was just the carb cleaning.

BTW, I live in Seattle, at sea level and it's a cool climate. This fix may not work for your local conditions.

Hope this helps others with problems with their Suzuki DF2.5 outboards.

Jon

Johnny
After testing under load what conclusion did you draw regarding get size.

also which gaskets should be ordered?

We have an ultrasonic cleaner. Would it be advisable following removal of the two jets to clean ultrasonically?

Thanks

[LuigiJC]

I have the same motor and had the same problem, from the first time I started it, the motor was hard to start and would idle, but would die as soon as you opened the throttle. I took it in and they change the carb. It was a bit better but still not right. Then took it in again, they had the Zuki factory rep there and they changed some jets and adjusted the screw under that tin cover. That seemed to do the trick, it runs like it should now, only needs 1/2 choke to start and no flat spot or hesitation. I really wanted a 2 stroke in this size but no one sells them here anymore, yet you can buy 2 stroke yard equipment. In fact I have 3 late model Echo yard engines, they all run on 50:1 Echo semi syn oil and they run great, do not smoke and hardly smell at all. Maybe the EPA regs are different for outboards vs yard machines but if Echo can do it why not Zuki, Yam and Tohatsu?

I know that the jets on these engines are very small and the fuel filter is small too. Yet with my yard equipment, I have had minimal problems over the years, only had to take apart carbs on the snowblower (Zuki 2 stroke) and the Echo blower one time each. If I start em up every 3-4 months no problems.

Just for the heck of it I took samples of my gas from the 2 containers I use for my 4 stroke machines and the gas was clean, I think there could have been some grit in the tank from the factory.

[johnkimura]

jets

Luigi, What year is your DF2.5? trying to determine if Zuki changed jet size in 2010.

[LuigiJC]

Mine's a 2012, bought in Dec '11. Don't know if they changed jet sizes or not but it ran bad right out of the box. BTW, the dealers would do better if when they sell a new motor, they run it in the test tank first to make sure it at least starts, runs and picks up RPMs right. That is something I will insist on if I ever get another small OB. Even a lawnmower shop (the ones I buy from) will test stuff before letting you leave with it, that is the service they can offer than Home Depot does not....

[LuigiJC]

Just wanted to give another update, since the dealer fixed it the second time, with changing the jets and adjusting the idle mixture, it has run great, no stumble at all, fast starts just needs a fairly fast idle speed. So these DF 2.5s can be made to run well but they need to do a better job getting the carb set up right in the first place. Kudos to the dealer and the factory rep....

[Techmaint]

I recently bought a used 2009 DF 2.5. The guy I got it from had it laying on the wrong side and the fuel that was in it was turning to varnish and lots of sediment and gunk in the tank. He hadn't had it running in about 2 years. Got it home, tried to start it, but no go, drained the fuel from the carb, which was basically engine oil, cleaned the fouled plug, added fresh fuel, and it started! Ran good at idle, but stumbled bad past that. Ran Seafoam in the fuel and sprayed Seafoam carb cleaner in the intake, ran a lot better then but still not good enough. drilled a tiny hole in the PMS cover..it's just a very thin aluminum cap covering the adjusting screw, pried the cover off with the drill bit and adjusted the screw with the engine running. Made a big difference, engine now runs perfectly. Tried it out under load on my zodiac and it worked like it should. Easy fix, I always run the engine with the fuel shut off when I'm done with the engine, doesn't take long for the fuel to turn bad and clog the tiny jets in these engines. I also put some Seafoam in the fuel just as a precaution. Hope this helps. Al

[Hal in TN]

Possible solution to running problems

I have followed the threads here because I was having a lot of problems with my 2012 DF2.5S as described here too. I may have a simpler solution for you guys that will cost you next to nothing and worthy of trying before spending a lot of money.

First of all, the re-jet and disassembly may be unnescessary as described in one message. Additionally, last I checked, the Browns Point Marina site is down so parts are hard to locate now. This is probably due to Super Storm Sandy pounding it. If anyone has an alternative for parts please post it here for us all.

I contacted my local Authorized Suzuki Warranty Dealer about getting my outboard repaired. The technician told me that my problem could be very simply fixed. He told me that small engines really don't like ethanol and that I should consider trying gas without it. I found a place only a few miles from home that carries non-ethanol fuel or "pure gas". The way you can find a station near you is to go to Ethanol-free gas stations in the U.S. and Canada and search for one by city and state. Additionally, ALWAYS use a fuel stabilizer to keep the fuel fresh and prevent "varnishing" which will clog your carburetor due to aging gas.

Using a funnel, I openned my fuel cap and poured the old gas from my buit-in tank into the 1 1/4 gallon can that I use for my outboard then put that fuel into my SUV. I went to my local auto parts store and bought a can of "Sea Foam" which is both a cleaner and conditioner and put the recommended amount in the gas can and filled it with non-ethanol 89 octane. I took my boat to the lake for a test run. It started first pull, every pull regardless of cold or warm. It idled perfectly and ran great. It went into gear smoothly without stalling after barely a few minutes idling at 1/2 choke. Throughout my test run it FINALLY ran smoothly at all throttle settings!

As far as fast acceleration of the throttle.... bear in mind that there is no accelerator pump on this small carb so DON't DO THAT! If you want fast hole shots, buy a bigger engine!

Another problem mention was that nothing seemed to happen when increasing throttle from 3/4 to full. I have the same thing with mine and notice only an increase of intake noise and no speed increase during full advance. Most small boats with very rare exception that we use this small motor on will come no where near acheiving "plane" so the load on the prop remains heavy and prevents full motor rpm. Unless a prop with less pitch can be installed, that problem is not able to be remedied but will probably result in minor performance increase. If anyone has a source for a lesser pitch prop, please post that here too.

If you plan to not use your motor for a period over a month, it would probably be a good idea to drain the carb and built-in tank for storage to prevent clogging.

In closing, I hope this is as helpful for you as it was for me! A few bucks and I am running fine!

Regards,

Hal in TN

[suzujet]

I know this thread has been dead for a little while, but I just stumbled upon it while looking through old threads...

I work at a Suzuki Outboard Dealership and Repair shop. I recently started as the sales manager here and quickly learned about the Suzuki 2.5 four stroke. My dad bought one and let me borrow it to backtroll in the rivers here in Michigan. When I got it from him it ran like crap, exactly how it has been described in previous posts. It's a 2011 that he got from a guy who used it a handful of times (no wonder he already wanted to sell it, it ran terribly). I had trouble with it starting, idling, accelerating, and staying running. Plus I had to choke it on every single start. When I talked to my boss and service guys they knew all about the issues. It appears to be a wide spread problem. They had several come back for warranty work before I started working here.

I brought mine in and spent a couple hours tearing the carb apart and cleaning every little thing possible. It runs much better now, but there is still the miss when trying to accelerate quickly from idle. Apparently this is normal on these motors and most small 4 strokes because of the small carb design. Personally, I will avoid buying the 2.5 in the future for that reason, but I'd take any of the other Suzuki 4 strokes in a heartbeat!

[Hal in TN]

I know this thread has been dead for a little while, but I just stumbled upon it while looking through old threads...

I work at a Suzuki Outboard Dealership and Repair shop. I recently started as the sales manager here and quickly learned about the Suzuki 2.5 four stroke. My dad bought one and let me borrow it to backtroll in the rivers here in Michigan. When I got it from him it ran like crap, exactly how it has been described in previous posts. It's a 2011 that he got from a guy who used it a handful of times (no wonder he already wanted to sell it, it ran terribly). I had trouble with it starting, idling, accelerating, and staying running. Plus I had to choke it on every single start. When I talked to my boss and service guys they knew all about the issues. It appears to be a wide spread problem. They had several come back for warranty work before I started working here.

I brought mine in and spent a couple hours tearing the carb apart and cleaning every little thing possible. It runs much better now, but there is still the miss when trying to accelerate quickly from idle. Apparently this is normal on these motors and most small 4 strokes because of the small carb design. Personally, I will avoid buying the 2.5 in the future for that reason, but I'd take any of the other Suzuki 4 strokes in a heartbeat!

Save your money on rebuilding your carb and run non-ethanol fuel with a stabilizer. Sea Foam has worked great for all my small engines. Local sources for this gas can be found at Ethanol-free gas stations in the U.S. and Canada and always drain the tank and carb when not using it for more than 30 days. Drain your old fuel from the carb and tank and refill with the new fuel. Install a new spark plug.

Small engines usually don't have accelerator pumps so rapid throttle advances should not be done. My DF 2.5 starts first and every pull and idles well with a few minutes of warm up at 1/2 choke. If properly maintained and operated, it is a dependable motor and doesn't need to be avoided.

[LuigiJC]

I can say that once they changed the jets and set the mixture, it has run fine with no flat spot at all. That little tin cover needs to be removed and the idle mixture needs to be set. Its just like back in the 70s when the stupid EPA mandated plastic caps on the carb mixture needles for cars. Many ran terrible till they got better at emissions but if I knew then what I learned over the years I worked on all my own vehicles, I'd have taken those caps off right way. I have an OMC Cobra 4.3 with a Rochester Quadrajet and I set the mixture every few years. No stupid caps. I paid for it and I'm setting it the way I want, EPA......

[LuigiJC]

OK another follow up. The engine still runs well. Here's something I noticed though, some small black flecks in the gas and in the tank. As sensitive as these small engines are to jet clogging, I wanted to investigate this. Well take off the gas cap and look at the underside of it. There is some black foam stuff inside it that was starting to come apart. I'm not sure if this stuff could actually get past the filter and clog the jets but I pulled it all out with a tweezer anyway. Serves no purpose that I could see. Might want to check it if you have one of these engines.

[Bassman37]

Post still active?

I realize that this is an old post so I wondered if this problem has been rectified by Suzuki on their newer models.

As I just took delivery on a 2017 model DF2.5, should I be expecting the same issues when I put it in the water up here in the North in a few months?

Thanks in advance,

Kevin

[Solarman]

Kevin, I'm not certain about that Gas cap, but in most cases where black flecks (like soot) are involved, it is related to "ethanol" fuel (without using a protective additive), causes deterioration of all (rubber) gaskets, fuel lines, diaphragms, etc..
Protective additives for ethanol fuel should be used in every tank full of fuel. Some ethanol fuels can go bad (turn yellow/orangeish color) within a month, additives can help prevent this phase-separation also.

Bringing up old threads, can be very misleading.

Good luck, post back if you have any other concerns.
Starting your own thread is the best way to ask questions too.

[SkinyG30]

Gas leak

On the topic of fuel, I am new to boating and just purchased a 2017 2.5 outboard. I did everything by the book during the minimal setup. I go out on my maiden voyage and open the gas vent, pull the choke out and flip the fuel switch to on and fuel leaks out of the bottom. I opened the top and could not actually determine exactly where the fuel was leaking but was definitely from the carburetor area. I did not over fill the tank. I know from the manual that you can drain fuel from the tank but it doesn't exactly show you how to do that. When I turn the fuel switch off, no more leak. I am really mechanicaly challenged, so I dont know how to correct the issue. Figured I would ask the forum before bringing it to be serviced. Engine is under warranty, so it shouldn't cost me to fix whatever the issue is, but hoping it is just an adjustment somewhere. Also when the issue is fixed, how dangerous would it be to run the motor after fuel going seemingly everywhere. Thank you for your time and expertise and helping a new bee who has zero knowledge about this stuff.

[Solarman]

Not being familiar with this motor, I'd recommend taking it in and show them what it's doing.
It sounds like one of the fuel lines may be loose, or not connected. If fuel is running out of the carb, then it may be the float is not working properly.

I'm sure they could show you what is wrong.

Good luck. Post back when able to let us know how it's going.