Cleaning carbs.

[DFW]

Got the boat in the water last Saturday. Had a marina get the engine all ready and told it was fine. Well it would not start. The guy who did the work took the carbs off twice to clean them. He put 15 minutes on it and said it was o.k. The engine was pickled and stored for 7 years before this.
It is a 2001 Mercury 90 h.p. 4 stroke with 4 carbs. I have clean fuel all the way to the carbs. I am presuming the inside of the carbs still had some varnish in them and the jets have clogged. Has anyone been able to clean the carbs without disassembling them?
I did get it to idle with no problems for a while and I guess it sucked up more crap. He used a special machine to clean them.
Thanks for any help. Dale

I least I got to use the boat tied to the dock. Can't wait for it to run now......

[GregF]

If he didn't take the bowls off and clean them, the crap was still in there.
It is usually better to take them off, take them apart and blow everything clean with carb cleaner. Best is to put the main body in a hot tank, if anyone still has one of those. I think EFI and the EPA makes them rare.

[Bamaman]

My boat will start on starter fluid, but acts like it's not getting any gas. I pulled the boat out of the boathouse yesterday and brought it home. (I have an old Yamaha 115 hp 2 stroke.)

Around the engine, there is a strong varnish smell. The fuel filter assembly has a screw off clear plastic bowl that appears to be "welded" shut. I suspect the 90/10 gasoline has separated and that it's the culprit. The fuel in the bowl is "dark" colored. The fuel pump has a rubber membrane that I suspect may have been affected.

I have ordered a new fuel filter assembly ($60), and a new fuel pump ($35). I'll be spraying everything down with carb. cleaner and reassembling the fuel system when the parts arrive.
I already have a new fuel line and bulb.

As far as the twin carbs, they were cleaned last year. It took me about 1 hour to pull'em, clean'em and reinstall. On 2 strokes, carb. kits are not usually required as long as you're careful to not hurt the gaskets. The only proper way to clean carbs. is through disassembly.

With a good engine manual as a guide, simple 2 stroke carbs are easily disassembled and cleaned. And, I'm certainly not a professional mechanic.

[GregF]

Yup a 2 stroke boat carb is about like one on a 53 ford 6 cylinder but a little simpler. (no accelerator pump and no choke)

[LocoCoco]

Sometimes you can get away with reusing the gaskets but often not. In fact, just a week or two ago I cleaned out the carb on my newly-acquired '99 Mariner 2.5 and after reassembly, the bowl gasket leaked. I didn't buy a whole carb kit but just the bowl gasket for an even $10.

To clean out the jets, I plunge them with a safety pin along with hosing them out with carb cleaner. And be gently on the float, you don't want to bend the metal things and inadvertently adjust the float height.

After cleaning, it's possible that a tiny piece of green death was missed and ended up plugging the jet again causing the motor to not start. However, on an engine with four carbs, it should still run on three cylinders with one carb down. There's no way all four carbs are plugged after cleaning unless you have the world's worst mechanic.




LC.

[BoatCop]

Before putting the boat up for any length of time, spray a goodly amount of Mercury Power Tune through the intake while the eninge is running. If it's going to be unused over the winter or longer, disconnect the fuel line, and run the engine until it stalls, spraying this stuff through the carb(s). (Don't disconnect the fuel line in fuel injected/non-carbureted models)



It's also available as a fuel treatment to add to your tank every few fill-ups to keep the fuel fresh and gaskets/seals viable.

[GregF]

The Merc VST has a drain plug. That is the best way to drain the system. Turn the motor over with the lanyard pulled so it won't start to get the gas out of the rest of the system with the drain plug out. If you have a spare fuel line connector, put it in the motor end to break the vacuum and let the gas flow.
You can bleed the high pressure side by wrapping a rag around the test port, push in the valve stem to release pressure, then open the fuel line by pushing in the red latch on a joint and pull it off.
There is usually not enough gas in there to worry about.
If you are storing the motor, pull the plugs and shoot some fogging oil in each cylinder.

[STEVEBRENDA]

Besides fuel, I would visual the gas lines and maybe even replace the bulb. Some of your symptoms are similiar to a gas line sucking air.

My 2 cents.

[waterlab]

[quote="LocoCoco" There's no way all four carbs are plugged after cleaning unless you have the world's worst mechanic.




LC.[/quote]
Reading lots of post at various sites, it's starting to look like a lot of the mechanics are really not worth much. I think some are just being either lazy are trying to complete as many jobs as possible. When I first bought our toon I took it to a "good mechanic"( around Smith Mountain Lake) to have to outboard gone through and fix anything that needed to be fixed, later I decided to check the carbs as it seemed to be running a bit rough, the third carb's float was way off when I checked the measurement, it should be 7/16"from the bowl rim, it was around 5/8's. Set it to where it should be and the motor ran smooth again and hasn't changed. That's when I decided to get a manual and study it in the off-season and do my own work. Haven't run into any of them yet that are worth 80p/h, hope to someday, not going to hold my breath.

[sjp]

drain bowls and fill with power tune, let it sit 30 mins, mix up some fresh gas with lucas tune up and quickleen, get it to run on the muffs up to 3k rpms ( i know not recomended, but it works) get engine hot, sporadically spraying power tune in a fan motion of intake.

Fill up with clean premium, and run the crap out of it, it is going to buck and then take off, buck and take off, also large amounts of smoke too.

This was told to me my Joe at mercury.

[playcat]

[quote="waterlab]
Reading lots of post at various sites, it's starting to look like a lot of the mechanics are really not worth much. I think some are just being either lazy are trying to complete as many jobs as possible. Haven't run into any of them yet that are worth 80p/h, hope to someday, not going to hold my breath.[/quote]

I just got my boat back after a nearly 3 week wait to get the carb rebuilt; my son went down to check it and it still stalls at idle, and floods like crazy on the primary side. I called the shop owner and told him, and I spoke with the guy that worked on it. He said he cleaned ONE side of the carb, but not the other!!! WTF????
I told the shop owner the first "visit" was free and I would pay when/IF the work is done CORRECTLY. I'm ordering a LOT of shop manuals today.

[DFW]

Took the carbs apart. Full of crap. Looks like they were never apart. Was trying to download a pic but not working. The carbs are KEIHIN BCF's. Does anyone know were I can download a diagram of this carb? Thanks.. Dale

[Bamaman]

A Clymer Mercury 4 stroke Outboard Shop Manual can be found at Amazon.com, and it'll be the best $20 you ever spend. It'll have carb rebuilding instructions with pictures.