Rebuilding Carb On 2004 115Hp

[J-Doc]

Quick example of who “doing it yourself” can save a ton of money.

Last year, my starter was making some gosh-awful squealing noises after engaged. When I asked my mechanic, I was told, “just buy a new one, I don’t work on starters”. Easy for him to say……that’s $190 I didn’t have.

After a little research on iboats, I found out that I could take the starter apart, spray some electrical cleaner from O’Reily’s on the armature and internal parts, apply a little anti-sieze lube to the bottom of the armature shaft (where the noise was coming from due to dust from the starter brushes) and when I put it back together, it worked like a charm. The problem was the inside parts of the starter was dirty.

For about $7 at O’Reily’s, I fixed my problem as well. Still using the same 32yr old starter that came on the motor.

[Bird Watcher]

I am with you on that, I have downloaded the manuel now and looks like removing the bowl, cleaning jet, replacing gasket is all that there is too it, as long as you don't bother the idle air screw should be fine. Around $7 per carb for gaskets.

Anybody had problems doing this?

Works like a charm. Been doing it 5 years on my own after spending time and money at the mechanic every year before that. You'll save a lot of both doing it yourself every spring.

[mosouthpaw]

Bassboat central has a good merc motor forum.

FWIW mercury quickleen can clean up an engine really well. i think overall the price of quickleen vs seafoam is enough to just use the quickleen plus the ethanol stabil

Id also replace your fuel filter and get a new fuel line and bulb.

[Stump bumper]

I have pulled and cleaned all four carbs, will pick up the gaskets Monday,bottom two bowls were dry, top two were full. I acutally heard a pop when I first blew out the bottom carb. Thinking about replacing fuel lines to the carbs, but they look good, seems like extra work just for a piece of mind. It's not hard to get the carbs off and clean, will let you know how they go back on.

[zarraspook]

I have pulled and cleaned all four carbs, will pick up the gaskets Monday,bottom two bowls were dry, top two were full. I acutally heard a pop when I first blew out the bottom carb. Thinking about replacing fuel lines to the carbs, but they look good, seems like extra work just for a piece of mind. It's not hard to get the carbs off and clean, will let you know how they go back on.

Now that you have the carbs off.... Check the REED valves !!! If they are cracked, broken, or leaking; they will allow back presser into the carbs... and the gas will not be sucked into the bowl...

But, if your lines are free (not pluged or collapsed) and the reed valves are OK the it has to be the needle valve / float assy. or leaking gaskets.....

[J-Doc]

I have pulled and cleaned all four carbs, will pick up the gaskets Monday,bottom two bowls were dry, top two were full. I acutally heard a pop when I first blew out the bottom carb. Thinking about replacing fuel lines to the carbs, but they look good, seems like extra work just for a piece of mind. It's not hard to get the carbs off and clean, will let you know how they go back on.

Good for you for taking it on yourself. Feels good to know you can solve a problem and save a ton of cash. I agree with the post above, check the reeds.

[Ranger Dave]

I have a 2002 Mercury 125 which should be very similar to yours. I rebuit my carbs last spring (part numbers below). Only the top two carbs have idle jets. The bottom two carbs only kick in about 1400 rpms. The book says that enough air flow goes through the bottom 2 carbs to keep the engine lubricated but not enough to support combustion. It kinda works like a 4 barrel carb system on a car where the car only runs on the front 2 barrels until you reach a certain point in the linkage or if you stomp on it. Take a look at the linkage side of your carbs at the top; only the 2 top carbs will have mixture adjustment screws because they are the only two carbs that have idle circuits.

The reason why your outboard doesn't die while spraying cleaner in the bottom 2 carbs is because there basically isn't any gas being supplied by the bottom 2 carbs at idle or slightly above idle because the carbs don't have idle circuits. However, on the two top carbs, since they are already supplying gas through the idle circuit, the engine floods out.

There is another similarity with a 4 barrel carb. Since the bottom 2 carbs don't have idle jets, on a rapid acceleration, the bottom 2 carbs will lean out instantly and cause a hesitation problem. To prevent this, your outboard has an accelerator pump that squirts liquid fuel directly into the crankcase just behind the reed valves. The accelerator pump is driven off of the throttle cam. It is a small aluminum housing with a white button on top that touches the throttle cam.

According to a Mercury Mechanic that I have been emailing, Mercury messed up their parts system a few years ago when they dropped the leading prefix number. This caused some duplication of part numbers which mainly affected the early 2000 model years. The original part number for the float needle was something like 1395-9595 1. They still make this needle but the part number was changed to 1395-879194011 and it is approximately $8 each. The gasket set for the carb is 1395-811223 1 and it about $6. The "carb kit" includes all of these parts but a few other items you don't need but it is over $30. These prices are cheaper than listed on Mercury Parts Express. They are from a place in OK at www.perfprotech.com where I buy most of my parts. They are about 80% of list. You can probably get these same parts over at Center City Marine or Bass Pro Service Center at Sunset and Campbell.

Do you think you have a problem just because the engine doesn't die when you spray cleaner in the carb or are you having specific problems?

[Stump bumper]

The problem I was having is it idles fine, shifts into gear fine out of the water with the dog ears on. When I put it in the water it dies as soon as I put it into gear.

While cleaning the carbs, I found a burnt wire behind the oil reserve that went to the stater, I have replaced that wire.

Just for some background, the engine had a fire about 3 years ago, due to a bad ground and I replaced most of the wiring but missed that one and it looked like it had worn through and was arking.

Thanks for the backgrond on the carbs, it makes a lot more sense now, but the carbs needed a good cleaning and it was easy relative cheap but probally not the problem. I am hoping the burnt wire on the stator was the problem and the stator is not the problem.

Before it started this it was cutting in and out at low RPMS but when I put the gas to it the problem would go away, so I was thinking a dirty carb or cloged fuel line. Now I am thinking it was just more power going through a bad wire. I will be able to try again Friday with fixed wire, clean carbs, reeds inspected. If I still have the same problem then I will know it is electrical and I just don't have the funds to replace any of those parts right now.

[Ranger Dave]

These engines have a rev limiter that grounds the ignition system when you exceed the specified rpm (around 5500 I think). Your condition kinda sounds like the rev limiter is kicking in too early or perhaps the wire going to the rev limiter is grounding out.

You might check your spark plug wires as well. I was having a some problems with idling and initial acceleration. Problem was a loose spark plug wire on the top cylinder. Since the engine idles on just 2 carbs, a loose spark plug wire on one of the top 2 cylinders can cause a momentary loss of power of 50%. Don't know why it got loose, but it has done it several times now. It doesn't fall off, it just slides up the spark plug about 1/4". It is close enough to fire the plug most of the time but will occasionally mis-fire and usually would mis-fire on acceleration as the acceleration caused the engine to shift and cause the spark gap to increase.

[J-Doc]

So did you get your boat fixed?