Motor Troubles

[bobowski]

I was wondering if anyone could help me out. I am currently having trouble with my boat motor. I have a 9.9 hp two stroke Mariner motor on my boat. The motor starts fine and I am able to drive slowly, but when I try and speed up it will run for about 10 seconds and then konk out on me. I just put fresh gas in the tank so it isn't a problem with the gas. Can anyone with any knowledge of boat motors please give me some advice on what it might be that is causing this problem? Any input would be greatly apprieciated. Thanks

Edited July 17, 2010 by bobowski

[Big Cliff]

I was wondering if anyone could help me out. I am currently having trouble with my boat motor. I have a 9.9 hp two stroke Mariner motor on my boat. The motor starts fine and I am able to drive slowly, but when I try and speed up it will run for about 10 seconds and then konk out on me. I just put fresh gas in the tank so it isn't a problem with the gas. Can anyone with any knowledge of boat motors please give me some advice on what it might be that is causing this problem? Any input would be greatly apprieciated. Thanks

 

Sounds very much like a fuel related problem, you might get away with running some SeaFoam through it, put some in the tank, run it for about 15 minutes then shut it down and let the SeaFoam work for an hour, if that doesn't do it, you might need a carb kit, not very expensive and fairly easy to install but adjustment on a 2 stroke is critical, too lean and you'll blow your motor very quickly. Try the SeaFoam first, don't play with the Lo/Hi speed jets. If it needs a carb kit you might be smart to take it to someone who knows what they are doing.

[misfish]

Had this with my 25 merc. Sticky needle valve. If you dont have the skill to take the carb apart,then do like Cliff said,try the foam first it may work.If not,take it to a marine mach.

[aplumma]

While obvious and easy to over look did you check to make sure the tank vent is open? Does the float bulb collapse as it stalls? I am sure that Big Cliff is correct though.

 

 

Art

[Bernie]

The guys have given you good advise.

Also be a good idea to look for a kinked fuel line.

Definitely a fuel flow problem.

I'd bet on a plugged carb.

[misfish]

While obvious and easy to over look did you check to make sure the tank vent is open? Does the float bulb collapse as it stalls? I am sure that Big Cliff is correct though.

 

 

Art

 

 

Who the hell runs outboard tanks these days, that have fuel tanks, that have to have thier caps half cracked open for air these days?????? Boy you guys sure are behind in yer time arent yaz.

 

Anyone I see these days with them steel tanks I say buddy,go plastic man. The rust particals will cause you nothing but problems.

 

The plastic ones do have a small plastic tab screw, that does have to be open.

Edited July 18, 2010 by BrianB

[pikehunter]

The plastic ones do have a small plastic tab screw, that does have to be open.

Ahhh yaaaa, that would be a tank vent. Who in the h== said anything about a metal tank? What did I miss? I didn't read that into Art's reply, but then again it is about 4:45 A:M and I could be missing something.

[Fish Farmer]

Sounds like a fuel problem to me also. Your talking Mariner, so it's not that late of a model. I had OMC's for years and had almost the same thing happen. The connection on the hose that connects to the motor had a rubber O Ring inside that got nicked, a very small nick in the O ring you could hardly see. It caused an air leak which sucked air. Have a look, it could be your sucking air some place in the fuel line hose or clamps. Not sure about Mariner but the older OMC's had fuel diaphram, could be that also. Remember cheaper first. Good luck.

[bobowski]

Thanks for all the good advice guys. I am going to pick up some Sea Foam today and give it a try. My fuel line is also pretty old and weathered. Maybe there is a small leak where air is getting into the line. That will be my next step if the Foam doesn't work. Thanks again.

Edited July 18, 2010 by bobowski

[Big Cliff]

Thanks for all the good advice guys. I am going to pick up some Sea Foam today and give it a try. My fuel line is also pretty old and weathered. Maybe there is a small leak where air is getting into the line. That will be my next step if the Foam doesn't work. Thanks again.

 

If the line is old and cracked, replace it anyway, it will just save you a problem in the future even if the SeaFoam works for now. We aren't talking big bucks to replace the line, CTC sells it by the foot for about $1.28/foot. If the line inside of the cowling from the tank connector to the carb looks old and dried out, change it too. If that line has started to break down, that junk will get into your carb and cause problems.

[Spiel]

If the line is old and cracked, replace it anyway, it will just save you a problem in the future even if the SeaFoam works for now. We aren't talking big bucks to replace the line, CTC sells it by the foot for about $1.28/foot. If the line inside of the cowling from the tank connector to the carb looks old and dried out, change it too. If that line has started to break down, that junk will get into your carb and cause problems.

 

 

Exactly, change the fuel lines, run the SeaFoam and hopefully you'll be golden.

 

 

[Sinker]

I had the samem problem with my 40 mariner this season as well. I replaced the gas line, put a full can of seafoam in the 25L fuel tank, and ran the hell out of it. She's running like a top now. Its a good idea to change your plugs once you run the seafoam too, you'll be surprised at the amount of crap the seafoam will burn out of your motor. Don't worry about the smoke, its doing its job if there is a lot of it.

 

If you don't run the motor a lot, I'd add the reccomended amount of seafoam in every tank of fuel, just as a stabilizer. I don't do that anymore, only because my fuel doesn't sit long at all. I'm on the water at least twice a week.

 

S.

[Guest ThisPlaceSucks]

similar problem on my mercury last season. as it turned out i had a bad plug with an improper gap. when i installed a new plug it was fine.

[pikeguy]

Who the hell runs outboard tanks these days, that have fuel tanks, that have to have thier caps half cracked open for air these days?????? Boy you guys sure are behind in yer time arent yaz.

 

Anyone I see these days with them steel tanks I say buddy,go plastic man. The rust particals will cause you nothing but problems.

 

The plastic ones do have a small plastic tab screw, that does have to be open.

 

 

 

 

 

I have a plastic tank that does not have a vent on it, The first time i had a problem with it was a Lakair the motor would not run properly and stall out. I loosened off the cap and it was fine

 

so i guess im only half way behind the times lol

[misfish]

Ahhh yaaaa, that would be a tank vent. Who in the h== said anything about a metal tank? What did I miss? I didn't read that into Art's reply, but then again it is about 4:45 A:M and I could be missing something.

[smally21]

Sounds like a fuel problem to me also. Your talking Mariner, so it's not that late of a model. I had OMC's for years and had almost the same thing happen. The connection on the hose that connects to the motor had a rubber O Ring inside that got nicked, a very small nick in the O ring you could hardly see. It caused an air leak which sucked air. Have a look, it could be your sucking air some place in the fuel line hose or clamps. Not sure about Mariner but the older OMC's had fuel diaphram, could be that also. Remember cheaper first. Good luck.

 

my 2 cents is the connections on the hose. a resort i frequent runs mercs and yamis and this behaviour seems to be the connectors