Smokey and bogging! Where to start?

[stinkynathan]

1982 (I think) Mariner 15m
684C s 018599

It finally warmed up enough for me to stick the motor in a trash can today. It started up pretty easy. It ran well for a while, then seemed to start bogging down and smoking a lot. It eventually died. Started it again and it smoked bad, bogged down, and died.

I let it sit while I took apart the throttle linkages that have play in them. Started it again after I got it back together. It ran OK for a little while again, then started bogging. The last time I started it I took this video. That's with the throttle all the way up. Any less throttle and it would die.

I'm new to 2-cycle, but definitely not to carbed engines. I've tinkered with my Harley enough to know at least a little bit about how things work. Come to think of it, I guess I've never had one malfunction on me, though.

Where do I start? Carb kit? Plugs and gas are both brand new.

 

[ben2go]

I would start with cleaning the carb(s) and checking the float height.Most engines don't require a kit for this.Another issue could be the points and condenser,I just replace them.Gap setting is usually on the plate covering the points.They are usually cheap.If it ran that good I'd say the coils are probably ok,but when they get hot they could be breaking down.Wost case,the carb(s) could be out of sync with the ignition timing,if your engine has this.I've yet to figure out how this works on my engine,but it must be spot on to run smoothly.

 

[stinkynathan]

I had the carb apart and have already cleaned everything out.

I just went out a few minutes ago to take picture of the plate on my transom and realized that I hadn't opened the gas tank vent when I was running the engine. That can't have helped.

I'll check the float height tomorrow before I leave town. Hopefully that will fix things.

 

[Loggerhead Mike]

it sounds like its flooding out. make sure your float is seating, you no just turn it upside down and blow in the fuel line.

my motor likes to blow the fuel pump element if i forget to unscrew the bleeder on the gas tank. im going on my 3rd now

 

[stinkynathan]

I went out and adjusted the float. It ran great again for about 45 seconds. I even got it into upper RPMs. When I brought it back down it wasn't smoking. Tried to adjust the idle because it sounded a little low. Engine died, then went right back to the smokiness and bogging I had before. Carb rebuild time?

 

[crappie-attitude]

A carb kit would be my first step. I know many say it isn't necessary, but I figure if I have it all apart, why not put the kit in it. I does sound like it's getting too much fuel. I've always worked on Evinrude, Johnson, and Suzuki so I'm not sure what your motor has, but when putting everything back together, make sure your hi and/or low speed adjustments are at factory spec. You can fine tune them later, but I generally always put them at factory spec. if I'm having problems.

 

[crappie-attitude]

One other thing....you said you have new fuel......are you positive it isn't too oil-rich? I'm sure you're fine there, just had to ask.

 

[LarryA]

Was the engine in storage up to now with the cylinders oiled?
Generally, with a 2 stroke, smoke meams burning oil, and that video showed a lot of smoke. Are you sure you have the mixture correct? This could also account for the stalling from the plugs starting to foul out. I would suggest using the mixture recommened your engine and not changing that unles you can accurately read the looks of the plugs under normal conditions.

 

[stinkynathan]

One other thing....you said you have new fuel......are you positive it isn't too oil-rich? I'm sure you're fine there, just had to ask.

I'm nearly 100% positive I mixed the gas correctly. I haven't done it before, but I followed the directions on the bottle when I mixed it.

Was the engine in storage up to now with the cylinders oiled?

He said he stored it over the winter without winterizing it and he thought the gas went bad.

Generally, with a 2 stroke, smoke meams burning oil, and that video showed a lot of smoke. Are you sure you have the mixture correct? This could also account for the stalling from the plugs starting to foul out. I would suggest using the mixture recommened your engine and not changing that unles you can accurately read the looks of the plugs under normal conditions.

I haven't adjusted the mixture a bit from the directions given on the bottle of oil, though I did add the proper amount of stabilizer to this tank.

I ordered a rebuild kit yesterday. I guess things are at a standstill until I get that kit delivered and installed. I'm sure it will be a good week and a half :x Might as well start on the decking project, I guess.

 

[crappie-attitude]

I couldn't watch the video before because I was at work and they have it blocked! After seeing it, I'd bet on the carb kit fixing your problem. Even with new fuel, it would have a tendency to pick up old junk and moisture. If it were my motor, I wouldn't be able to resist starting it and spraying Sea Foam into the carbs. just to see if it clears things up some. If you do this though, be sure you leave your oil/gas mix hooked up as the Sea Foam provides no lube by itself. Otherwise, have fun with the decking.

 

[stinkynathan]

Another addition to the ongoing saga.

Got home from out of town today and it's 60 degrees here. First nice day this spring. Figured I'd give it a start, hoping that it was a cold weather bug or something. It was started up before I even got to the end of my pull. It ran awesome again for about 1 minute, then started smoking really bad again.

I let it sit for a few hours, then came back out to repeat the process with my digital camera. It started right up again and ran for a little while just fine, after getting past the initial 10 seconds of smokiness. After a bit (just after I walk around to the other side of the motor), things bog down and it dies. Starting it again results in tons of smoke.

https://www.youtube.com/watch?v=1a3Us0zKv4I

Is it possible that this is a heat-related problem, instead of a carb one? It seems to start dying right as it's warming up.

Yes, I'm slightly obsessing over this. I could just leave well enough alone until I get the carb kit in the mail, but if I can fix it before then I'll probably get on the water one day. It's supposed to be 60+ all week long here and I don't have to work Thursday or Friday...I'm sure I won't make it, but I can hope!

 

[crappie-attitude]

Are you choking it to get it to restart after it cuts off? It's very unlikely related to the temp of the motor. If you're choking to get it started each time, the motor will run off the motor induced from the choke for a period of time, depending on the RPM's, but will not be able to keep running if the carbs aren't right (blocked, not adjusted, bad float, etc). If you want to play with it while waiting for the carb kit, you can do some checks to rule out some issues....gas tank vented?...no air being sucked in through the fuel line or fittings (tank to line, line connections, line to motor, motor hoses)?

 

[Quackrstackr]

Is that oil smoke or steam? It could very well be a heat problem and you could have a cracked head or water jacket.

You mention mixing oil according to the bottle... don't mix according to a bottle. Mix according to what that particular engine is supposed to have. Some are 50:1, some are 100:1.

 

[stinkynathan]

Are you choking it to get it to restart after it cuts off? It's very unlikely related to the temp of the motor. If you're choking to get it started each time, the motor will run off the motor induced from the choke for a period of time, depending on the RPM's, but will not be able to keep running if the carbs aren't right (blocked, not adjusted, bad float, etc). If you want to play with it while waiting for the carb kit, you can do some checks to rule out some issues....gas tank vented?...no air being sucked in through the fuel line or fittings (tank to line, line connections, line to motor, motor hoses)?

I don't choke it after it's died as a rule, though at the early stages of this I'd try the choke in different positions after it had died. I wouldn't start with any amount of choke and it started but smoke a lot without the choke.

I know the tank is venting.

What are some proper baseline settings for these carbs? I have the mix set at 1.5 turns out like my Seloc said, but it doesn't going into any depth on tuning.

...wishing I would have bought the factory Mariner manual now instead.....

 

[Loggerhead Mike]

i just watched your vid. looks to do the same thing my motor does.

check your fuel pump and the diaphram gasket. mine gets a small pinhole or tear in the pump element (looks like a small baloon), and sucks gas into the crank. it will start but not gain any rpm and die out, plus the smoke boiling out of it.

 

[stinkynathan]

i just watched your vid. looks to do the same thing my motor does.

check your fuel pump and the diaphram gasket. mine gets a small pinhole or tear in the pump element (looks like a small baloon), and sucks gas into the crank. it will start but not gain any rpm and die out, plus the smoke boiling out of it.

Interesting....

My carb kit shipped today from Washington, so I should have it by the end of the week. Of course, we don't have school Thursday or Friday and I'll be gone all weekend so I won't get a chance to work on it until late Sunday. Did I mention that it was 73 here today and we'll be in the 60s all week? .... ... ...

If the carb kit doesn't fix things, I'll go the route of the fuel pump kit next. I should have just ordered both at the same time, but $33 for the carb kit, another $40 for the pump kit, and shipping all add up quick! **** money hole! Hopefully I can get this maintenance done this season and not have to worry about it for a few years.

 

[stinkynathan]

Got the carb kit today and installed it tonight. Motor starts and runs great. The lugging and smokiness at idle is gone, but it does seem to be a little smokey still at higher RPMs. I'll have to wait until I can get it on the lake before I make any judgment on that. Runs great in the trash can though!

Any suggestions on setting mix and idle speed? I have it set at 1.5 turns out from seated now. Idle speed hasn't been touched much since I got it.