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Rebuilding Mercury carbs


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Carbs are back in and ready to tune in the morning. On a side note, you got me curious about the wires from the stator and ignition. When I first bought my boat in 2016 it had been sitting for 3 or 4 years. It didnt run well, and would only rev half way and then cut out and had issues starting again. I took it to a mechanic because at that time I wasnt willing to tackle a project like that. The more I looked tonight, the stator and switch box look like what the mechanic replaced. The wires are new and the date is 2016 on a date sticker. Here's what it looks like on my motor, and my finished carbs. Goodluck. It appears alot of this wiring is pretty easy to get to.

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Yeah, here is a picture of the trigger I just took out this evening. The white and black wire is toasted all the way back to the trigger.  The new one should be here in a few days.  Hoping it did not damage the switch box. The box is an easy to replace, but expensive.  

20200427_173504.jpg

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Nice looks good. I had a weird experience tuning my carbs the other day. Motor starts, idles great. I went out on the water and ran it for probably 15 mins. Fadlst, slow, idle. All looked good. Then it cauoghed and died. I was about to start it again. Ran fine for the next 15 mins and coughed and died again. It seems to be getting plenty of fuel. And it idled for 5 mins just fine before that happened. I know the carbs are clean so shouldn't be an issue there. Fuel pump looked good so I didnt replace it. Any ideas?

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2 cents worth,

Do you have a tank so you can run the motor on the trailer?

If you can replicate the problem on the trailer you can diagnose if its a spark or fuel problem. 

I would check to see if your losing prime first. Coughing sounds like it might be fuel related.

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Yeah. That was my thought. I changed the stock fuel filter to a glass aftermarket one when I changed the fuel lines. I am going to put the stock fuel filter assembly back on to see if that helps. My concern is that the aftermarket one is more restrictive than the original. The motor ran well, and never did this before I cleaned the carbs so I'm thinking it's something I changed. 

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Fuel line air or gasket leaks 

 

Tank vent . 

 

 

Just because you cleans the carbs , doesn't mean that residual particles in the fuel lines haven't gotten in the jets again.  This happened to me no less than 5 times . Had my carb off that many times . 

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On most Mercury 2S outboards it's a really good idea to inspect and replace the reeds once you have the carbs off. I've seen many a "carburetor" issue that was really a reed block issue. They wear out and need replacing every so often. 

 

Chuck

Edited by Chuck Smth
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Thanks everyone. I'll play more with the mixture. It's hard to believe that this motor never did this, then I clean the carbs, and there would be something major wrong. It also has all new fuel line and new fuel filter. I'll put the original filter back on and tune it more. I'll double check all the bolts and seals and make sure I'm not getting an air leak somewhere. Also, it's not hesitating during acceleration at all. Super responsive. I literally let it idle for 5 mins on the lake. Then some high speed. Then let it idle for 5 mins. No problems. Then slowly went in to the dock, put it in neutral and it died. I really think it's a fuel supply issue. I guess I'll know more saturday

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Another thing you can do is start it up with cover off. Get her idling and then spritz water around the bas of the carbs, etc. If the idle changes you may have found an air leak. Obviously, you don'w want to spray anything electric or into the carbs. Sometimes when they get cantankerous after a good warmup it;s the stator or another electrical problem but looks like you have that covered. 

 

Chuck

Edited by Chuck Smth
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Good idea. I'll check for an air leak too. I'm going to through it on the muffs to start saturday. I can check the idle and this issue before heading to the lake for final tune in the water. With the weather nice saturday I'm sure there will be a bunch of people at the launches.

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I think I found it. I took another look at the carbs. When I primed the bulb with the engine off, gas was seeping from the seal of the upper carb to the fuel bowl all around the carb and dripping onto the lower carb. I'm assuming if gas is coming out, air could get in. I know your not supposed to do it, but I threw the old seal back in. I hooked it straight to the gas tank and no more gas leak. I'll put it back together in the morning and test. I either overtighten the seal, or the new one wasnt quite right. Here's to hopefully be back fishing by sunday morning

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That was it. Ran it on the muffs this morning and it ran great. No more gas leaking from that seal. Went out for a spin on the lake. Started and ran great. Thank you all for the responses and help.

 

Back to fishing in the morning, around all the logs and debris it the lake from the storms 😆

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