1984 Mercury 200HP V6 - Leaking Carb, fuel issues

[wcsd106]

First off... UGH... another year with a new set of problems on my aging 200HP Mercury engine, but the way I look at it, I fixed electrical problems last year and the motor ran like new... guess this year it's carb issues.

I have had the boat on the lake once already this year and ran without any issues. This afternoon I got the chance to go out again.

Problems:

1. The primer bulb didn't seem to get very hard, but it firmed up somewhat and I decided to try to start the engine.

2. When I went to start the engine, it turned over a few times and acted like it was going to start, but then I heard what can only be described as a backfire and turned around to see flames near the bottom of the engine. These flames were extinguished immediately using the fire extinguisher and I opened the cowling of the engine to inspect it for damage.

3. I saw no visible damage, but I did notice that there was fuel that appeared to be leaking from the bottom carburetor.

I did not make any further attempts to start the engine after this.. one fire on the water was enough for me and I am just grateful it was just some very small flames.

I will be doing a better inspection tomorrow to see what I can find wrong with the carbs.

The last time I inspected the spark plugs, it looked like my bottom two cylinders were getting a little too much fuel... I would assume this is probably connected to my carb problem as well.

Since it's been at least 10 years since the carbs have been rebuilt, would it necessarily be a bad thing to go ahead and pull them and rebuild all 3 carbs?

Any ideas, as always, are appreciated. Thank You

 

[j_martin]

Re: 1984 Mercury 200HP V6 - Leaking Carb, fuel issues

Carb gasket kits are cheap. You probably have a little debris in then from deteriorating fuel lines. I'd say it's time for carb kits, (gaskets are likely all you'll need) fuel pump kit, and all new hoses internal and external.

Not really a big job, maybe an afternoon under the shade tree, but well worth the effort. Probably less than 100 bucks total in parts.

BTW, with the carbs off, the bleed line system is readily accessible for inspection. Test the check valves and inspect the condition of the lines.

If you really want to do a good tune up, get a reed plate gasket and pull the reed plate and inspect the reeds. If they're suspect in any way, throw in a set of Chris Carson fiberglass reeds. His parts are great, and his customer support borders on nagging.

Hope it helps
John

 

[aussieflash]

Re: 1984 Mercury 200HP V6 - Leaking Carb, fuel issues

Not really a big job, maybe an afternoon under the shade tree, but well worth the effort. Probably less than 100 bucks total in parts.
Lol,I just spent over 3 hours getting my carbs off.They really cram them in on the old V6.
Also check your float levels and needle n seats.

 

[wcsd106]

Re: 1984 Mercury 200HP V6 - Leaking Carb, fuel issues

Been looking over the carbs today at the house. When I squeeze the primer bulb, the bottom carb is gushing fuel. I've attached a video that I took to show what it's doing.

The other two carbs appear to be functioning correctly.

 

[j_martin]

Re: 1984 Mercury 200HP V6 - Leaking Carb, fuel issues

Not really a big job, maybe an afternoon under the shade tree, but well worth the effort. Probably less than 100 bucks total in parts.
Lol,I just spent over 3 hours getting my carbs off.They really cram them in on the old V6.
Also check your float levels and needle n seats.

You need more than a pair of vice grips, Oh, and the cover lifts off and out of the way.

Really, they're not all that tough with ordinary hand tools, except it takes a decent end wrench to get to a couple of the carb mounting nuts. Fat, farm store wrenches won't fit.

 

[j_martin]

Re: 1984 Mercury 200HP V6 - Leaking Carb, fuel issues

Been looking over the carbs today at the house. When I squeeze the primer bulb, the bottom carb is gushing fuel. I've attached a video that I took to show what it's doing.

The other two carbs appear to be functioning correctly.

Needle valve is stuck open, either bad, from debris, or seat came loose. '84 might have a sunk foam float in it.

Off it comes. It really wouldn't hurt to take all 3 off and make a project out of it. I'm sticking by my claim that debris is coming from somewhere, probably a fuel hose inner tube, and it should be all cleaned up and repaired properly.

 

[wcsd106]

Re: 1984 Mercury 200HP V6 - Leaking Carb, fuel issues

John,

I believe you're right. I pulled the carb this afternoon and disassembled it to check it out. I found a piece of trash in the right hand side needle seat. The floats look good. They are plastic and I can't find any holes.

After removing the trash from the seat, I blew through the fuel fitting. Air would travel through it, until I lightly pressed on both needle valves... then air would not flow through, so the garbage I found may have been my problem.

I looked here at iboats.com and the prices for new needle valves and seats aren't too awful bad.. Sierra 18-7233 is $12.99/ea

Would it be beneficial to go ahead and change out the needle valves and seats while I'm at this just for good measure, or would a cleaning probably take care of all my problems?

Also. I'm going to order 3 of the gasket sets and redo all 3 carbs while I'm at it. Sierra 18-7005 is $4.99 each or Mallory 9-37300 for $5.39 Is there any real difference between the two brands other than a minor price difference?

Hoping to get the parts ordered tomorrow and with any luck have the motor back up and running when I go on vacation week after next. Thanks

 

[j_martin]

Re: 1984 Mercury 200HP V6 - Leaking Carb, fuel issues

John,

I believe you're right. I pulled the carb this afternoon and disassembled it to check it out. I found a piece of trash in the right hand side needle seat. The floats look good. They are plastic and I can't find any holes.

After removing the trash from the seat, I blew through the fuel fitting. Air would travel through it, until I lightly pressed on both needle valves... then air would not flow through, so the garbage I found may have been my problem.

I looked here at iboats.com and the prices for new needle valves and seats aren't too awful bad.. Sierra 18-7233 is $12.99/ea

Would it be beneficial to go ahead and change out the needle valves and seats while I'm at this just for good measure, or would a cleaning probably take care of all my problems?

Also. I'm going to order 3 of the gasket sets and redo all 3 carbs while I'm at it. Sierra 18-7005 is $4.99 each or Mallory 9-37300 for $5.39 Is there any real difference between the two brands other than a minor price difference?

Hoping to get the parts ordered tomorrow and with any luck have the motor back up and running when I go on vacation week after next. Thanks

Needle valve is probably fine. Find the source of the debris and fix that. Hoses are suspect.

 

[aussieflash]

Re: 1984 Mercury 200HP V6 - Leaking Carb, fuel issues

Half way through servicing my V6 carbs.Cant hurt to replace needle n seats,definitely replace gaskets and give body a soak in carb cleaner and blow out.Im replacing all 6 needles and gaskets while its off the motor.

 

[wcsd106]

Re: 1984 Mercury 200HP V6 - Leaking Carb, fuel issues

My plans at this point are to replace the lines coming from the fuel pump and between the carbs. The fuel pump was replaced last summer. I did run into problems last time out where I had a primer bulb pretty much disintegrate... could be leftovers from that got into the fuel line. The fuel lines from tank to filter to engine are all brand new, the only lines left to replace are the ones from fuel pump on up to the carbs.

I am headed to get the carb gasket set and get the carb back on... I'll see if that will last me the rest of the season and then plan on rebuilding all 3 carbs this fall when I'm not on the lake.