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6HP outboard engine sputtering

Adam D

.
Sep 8, 2017
12
Catalina 22 Harrison Lake
I have a Suzuki 6HP 4 stroke outboard that I am having issues with. It starts fine but will sputter and die when I increase the throttle. It doesn't matter if its in neutral, forward, or reverse. The engine will run when the throttle is kept at or below the starting ignition position. It will run in that range with no issues but there is what sounds like obvious fuel starvation when the throttle is increased the moment I cross that ignition start line on the throttle handle. I changed the gas and the fuel filter and tried using both the internal and external tank with no success. I am now believing that the issue must be in the carb. I am assuming some clogged jets. I grabbed some carb medic and will go out and spray the carb and give that a go. If that doesn't help then I guess I will take the carb off and go from there. Anyone go through this and have some pointers for me? Would there be 2 sets of jets, one for the low end and one for high rev?
 
Sep 14, 2014
1,049
Catalina 22 Pensacola, Florida
Probably the run jet as idle jet seems to be working fine.
 
May 17, 2004
3,433
Beneteau Oceanis 37 LE Havre de Grace
If it's a manual choke try running it partially or completely choked. If it runs better that way it's likely a clue somewhere in the carb. Assuming that's the case you've got the right idea - try the spray first, then disassble. Spray any holes you can see with the cleaner and soak as much as possible.
 
Oct 24, 2010
2,391
Hunter 30 Everett, WA
It sounds to me like classic E10 gas issues. Pull the fuel bowl off and spray it good with carb cleaner. Or better yet, disassemble the carb and hose it out with carb cleaner. Be careful to keep it out of your eyes and wear gloves.

Ken
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
EVERYBODY has had this problem with outboards until they learn how to manage fuel storage and rebuild carburetors. Get the service manual for the motor. An ultrasonic parts cleaner a good way to get the deposits out of your jets and passages. You won’t spray your way out of this problem.
 

Ross S

.
Oct 20, 2011
120
Precision 21 Great Sacandaga Lake
EVERYBODY has had this problem with outboards until they learn how to manage fuel storage and rebuild carburetors. Get the service manual for the motor. An ultrasonic parts cleaner a good way to get the deposits out of your jets and passages. You won’t spray your way out of this problem.
I had problems with my new 6HP Tohatsu not long after I got it. I knew nothing of fuel management or the dangers of ethanol. And unbeknownst to me, my fuel separated. I got to the boat one day and had a really hard time starting it, but it started and I went out. At the end of the day I could not restart the motor at all and had to sail back into my dock.

It turns out that the o-ring in my fuel connector had swelled (from the alcohol) until it choked off the fuel flow. I replaced the gas and the connector and was able to get the motor running. But it didn't idle smoothly or reliably. I learned how to dis-assemble the carb and clean it. (Disassemble, dip in a bucket of carb cleaner for at least 4 hours, blow the jets out with spray carb cleaner). But after periods of time I'd start having problems again even though I was keeping my gas fresh and using stabilizer. As it turns out, the anodizing in my fuel bowl was flaking off and causing problems...which I suspect is related to my initial problems with fuel separation.

I ended up replacing the carb with a new one. I found a source of ethanol free gas and I use Stabil in that and still change it after a month. I've never had a fuel related motor problem again.
 
Apr 27, 2010
1,156
Hunter 23 Lake Wallenpaupack
My 8HP Honda has a low speed (idle) and hi speed circuit. If you have to take off the carb, I would recommend dipping in proper carb dip, and not just spraying with carb cleaner. Once you go to all the trouble of removing it, why just spray it and then find you have to remove it again? I have not had issues with the hi speed circuit, but the idle jet does clog every so often. On the Honda it unscrews from the top of the carb, so it is easy to remove, push a plastic "wire" through the center hole, spray with cleaner and then install.

I also use ethanol free gas (refurbished station near the boat now has it) and add Stabil. We just added a 19 ft bowrider to the fleet (yes, I'm a traitor but the wife wanted one, and the sailboat is temporarily out of commission to due to rub rail damage) with a 27 gal tank, and I am going to try to keep it supplied with E0 using a 5 gal can from that station; E10 is about 2.99 here, their E0 is about 3.85 and the E0 at the on-water marina is 4.65. Ouch.
 
Nov 26, 2012
1,520
Hunter 34 Berkeley
Classic ethanol in the gas issues. Pull the carb and clean it with carb cleaner. I suggest keeping a spare carb so you can switch them out quickly and always have a clean one available. Also, get a good fuel filter and install it in the line from the remote tank to the engine as close to the engine as possible. Ethanol dissolves the rubber in the hose and sends the gunk into the carb. It also attracts water. You may notice some rust on steel components in the carb like screws, etc. Finally , make a habit of running the engine dry at the end of each use.
 
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tjar

.
Aug 8, 2011
166
Hunter Legend 35.5 Tacoma, WA
This sounds like a simple matter of a clogged high speed jet. All of the above is good advice to prevent this from occurring, but the problem now is to clear the jet. You will need to disassemble the carburetor and remove the fuel jet. Hold it up to the light to see if it's partially blocked. You can try blowing through it first to remove the clog, but be careful about using anything to pry it out. The jet is soft and can be easily damaged. Reassemble and you should be good as new. Then, be sure to follow clean fuel practices in the future.
 
Apr 27, 2010
1,156
Hunter 23 Lake Wallenpaupack
I don't use wire to clean orifices in carbs, because (as noted by tjar) it can damage the jet. I found that floss threaders work well - you can buy them at any drug store or big box. If you split the loop part open, the plastic "wire" from the loop is tiny and stiff enough to get in even my low speed jet.
 
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Adam D

.
Sep 8, 2017
12
Catalina 22 Harrison Lake
This sounds like a simple matter of a clogged high speed jet. All of the above is good advice to prevent this from occurring, but the problem now is to clear the jet. You will need to disassemble the carburetor and remove the fuel jet. Hold it up to the light to see if it's partially blocked. You can try blowing through it first to remove the clog, but be careful about using anything to pry it out. The jet is soft and can be easily damaged. Reassemble and you should be good as new. Then, be sure to follow clean fuel practices in the future.
I took the carb apart and blew it out. No visible gunk or anything in the carb. Appeared clean and dry. Blew out the jets with air and seemed as though everything was in fine shape. Cleaned out everything anyway with carb cleaner and reinstalled. Still having exact issues. Haven't changed the spark plug, will do that tomorrow and hopefully that will solve it. One thing to note, it seems to run well when half choked
 

gdudik

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Oct 25, 2017
87
Catalina 22 Vancouver, WA
might make sense. A rich mixture is easier to ignite than a lean one.
 
May 24, 2004
6,769
CC 30 South Florida
Still having exact issues. Haven't changed the spark plug, will do that tomorrow and hopefully that will solve it. One thing to note, it seems to run well when half choked
These carburetors get gummed up and can be rather difficult to clean and sometimes the best solution is to replace the carburetor. But before you do anything insure that you have good flow of fuel all the way from the tank to the intake hose to the carburetor. Get a good carburetor cleaner, disassemble the carburetor and soak all the metal parts overnight. Using compressed air blow through all the orifices of the body and jets, put back into the carburetor cleaner and stir the parts in the cleaner. Run compressed air again to dry the parts. Reassemble the carburetor making sure all moving parts are moving freely, that gaskets are properly seated and tightened and give it another try to see if there are any improvements. You may repeat the cleaning procedure but if after two times there is no improvement consider replacing the carburetor.
 

Ross S

.
Oct 20, 2011
120
Precision 21 Great Sacandaga Lake
I took the carb apart and blew it out. No visible gunk or anything in the carb. Appeared clean and dry. Blew out the jets with air and seemed as though everything was in fine shape. Cleaned out everything anyway with carb cleaner and reinstalled. Still having exact issues. Haven't changed the spark plug, will do that tomorrow and hopefully that will solve it. One thing to note, it seems to run well when half choked
Blowing it out is often not enough. Soak it in a bucket of actual carb cleaner for 4 hours. After that use spray on the jets.
 

jviss

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Feb 5, 2004
4,627
Tartan 3800 Westport, MA
You won’t spray your way out of this problem.
+1 on that.

I have rebuilt many carburetors. I use a 1 gallon can of pro carb cleaner that comes with a parts basket inside.

One still has to know what one is doing. The carb should be disassembled for cleaning. Some parts may be harmed by the cleaner. Some carbs have one-use seals, like Merc fuel pumps on the smaller engines. If I'm going to clean it to this extent, I apply a rebuild kit in the process.

That said, a Suzuki carb like this is probably less than $150, so it might be worth looking into a new one. After that, make sure you drain or run-off any fuel before storage.