6hp, 1974 fuel dripping out carb

[scott_maier]

Motor is driving me batty. I've got fuel coming out the carb after a few pulls and the motor won't idle well or start very easily. I can spray fuel directly into the carb and it will fire up. It's weird because fuel is pouring out the throat of the carb but not going in!

compression: 85 psi on each cylinder, took off head and polished flat, cleaned tops of pistons, new head gasket, checked thermostat and put back with new seal and gasket

ignition: new coils, points, condensers, spark plugs, timing is good i checked it with timing light (when i had the motor idling), the spark will jump a 1/4" gap on both wires.

Carb: Rebuilt carb(twice) with poly float(the 2nd time), I did remove the welch plug covering the idle holes - cleaned and put a new one in.

Fuel pump: I bought a rebuild kit off ebay and installed it. It seems to be working good. I can remove it from the crank case and squeeze the primer bulb and no gas leaks out the hole on the back. It will also fill the carb bowl and pumps when the motor is running.

Gas: I can hook the tank up to my 55hp johnson and the motor will fire right up so i'm thinking the gas isn't bad, it' about 2 months old though.

-New reed valves, I polished the reed plate with sand paper on a granite block and re-installed with new gaskets.

I don't know why the gas keeps pouring out the carb throat after a few pulls. I'm wondering if the rebuilt fuel pump is causing some kind of problem.

I'm at my wits(and monetary) end on this. Any help will be greatly appreciated. Thanks in advance...

 

[coinman1947]

Re: 6hp, 1974 fuel dripping out carb

Hey scott, I sure hope you get some responce to your problem with the 6 hp, for your sake and it would be good info for me if i ever have this problem, I wished i could help ya, but i bet someone at there will respond, this a great site for sure. this is mine.- I had my boat out to the lake 2 times now and it seems to run great, all i did was put a water pump impeller in it and i added a pee hose to it. good luck

 

[tx1961whaler]

Re: 6hp, 1974 fuel dripping out carb

Appears that the float is stuck wide open.

 

[scott_maier]

Re: 6hp, 1974 fuel dripping out carb

Appears that the float is stuck wide open.

I know, but it shouldn't be. If i blow thru the fuel inlet port air flows until i turn the carb upside down then it stops. I'm gonna take the fuel pump off and check that again.

 

[scott_maier]

Re: 6hp, 1974 fuel dripping out carb

Hey scott, I sure hope you get some responce to your problem with the 6 hp, for your sake and it would be good info for me if i ever have this problem, I wished i could help ya, but i bet someone at there will respond, this a great site for sure. this is mine.- I had my boat out to the lake 2 times now and it seems to run great, all i did was put a water pump impeller in it and i added a pee hose to it. good luck

Are u rubbing it in or what????

 

[Daviet]

Re: 6hp, 1974 fuel dripping out carb

The needle and seat is the only way gas gets into the carb. If it is seating properly no gas should be able to get past it.

 

[Daviet]

Re: 6hp, 1974 fuel dripping out carb

Another thought, when you overhauled your carb you did make sure and install the nozzel gasket (#21 below) didn't you?
http://www.ishopmarine.com/ishop/js...CatFilter=BRP&eCatSupFldr=supplier-100-005-EJ

 

[coinman1947]

Re: 6hp, 1974 fuel dripping out carb

no way!!!! i'm all for ya fix it !!! just glad mine ain't do that!!! I'll be watching this post, please let us know what fixes this problem!!!!

 

[scott_maier]

Re: 6hp, 1974 fuel dripping out carb

Another thought, when you overhauled your carb you did make sure and install the nozzel gasket (#21 below) didn't you?

Yeah, i did that. thanks

 

[scott_maier]

Re: 6hp, 1974 fuel dripping out carb

it's definitely a float problem. I adjusted it so it would positively close, put it on the engine and it didn't flood, but of course the bowl didn't fill. But if i adjust it so it is parallel with the body of the carb it floods. If i adjust it so it is slightly at an angle it still floods! I've got it now so it there is a little resistance when I blow into the fuel inlet port, but still closes when i turn it upside down. I haven't put it back on the motor cause it's 95 outside and i'm taking a break!

 

[Monte1961]

Re: 6hp, 1974 fuel dripping out carb

Heres another thing also Scott. The tang where needle rides could be slightly bent to far also. that alone would explain why your initial setting did not work. I am glad to hear that you pitched old cork float in the burn pile. I have same motor only a 76 6044A and it's a peach! Good luck and let us know you make out!

 

[Daviet]

Re: 6hp, 1974 fuel dripping out carb

Silly question, you don't have the float in upside down do you?

 

[scott_maier]

Re: 6hp, 1974 fuel dripping out carb

Silly question, you don't have the float in upside down do you?

nope, I actually flipped it over to see if i did, but it's definitely right side up

Heres another thing also Scott. The tang where needle rides could be slightly bent to far also. that alone would explain why your initial setting did not work. I am glad to hear that you pitched old cork float in the burn pile. I have same motor only a 76 6044A and it's a peach! Good luck and let us know you make out!

As far as i can tell the tang isn't even close to touching anything. I've had the carb off two more times since my last post and tweaked the float. Now it doesn't flood quite as bad, but it won't fire at all. The bowl is filling though. Maybe I'm getting close, but I gave up and worked on other things. Maybe during the week I'll have a chance to work on it again...It's driving me nuts cause this thing should run.

 

[scott_maier]

Re: 6hp, 1974 fuel dripping out carb

Well i started playing around with this motor again last weekend and it still has the same problem. Fuel just drips out the throat of the carb, i don't get it. I took the carb off again, took it apart, put back together and same problem. The motor will run, but it is definitely rich and i've got gas dripping out of the carb throat. I'm about to throw in the towel...

 

[hidef]

Re: 6hp, 1974 fuel dripping out carb

Take it in steps it has to be something simple because these engines aren't that complicated.

I am wondering if something is caught under the needle valve and it is preventing it from seating properly before you pull it back off though I would go through the standard cold starting procedure with the cowl off.

With the engine off when you pump of the primer bulb on the fuel hose does it get hard? Or does it stay soft? Can you see fuel spray out of the carb? If the bulb gets hard the float is working properly and it is preventing fuel from getting into carb. So then the issue might be with the jets. The low speed jet should be adjusted 1 1/8 to 1 1/2 turns out the high speed should be about the same but will need to be adjusted with the motor running at speed.

Good luck

 

[scott_maier]

Re: 6hp, 1974 fuel dripping out carb

Take it in steps it has to be something simple because these engines aren't that complicated.

I am wondering if something is caught under the needle valve and it is preventing it from seating properly before you pull it back off though I would go through the standard cold starting procedure with the cowl off.

With the engine off when you pump of the primer bulb on the fuel hose does it get hard? Or does it stay soft? Can you see fuel spray out of the carb? If the bulb gets hard the float is working properly and it is preventing fuel from getting into carb. So then the issue might be with the jets. The low speed jet should be adjusted 1 1/8 to 1 1/2 turns out the high speed should be about the same but will need to be adjusted with the motor running at speed.

Good luck

Yeah, I know these engines are simple, that's why it is driving me crazy. I rebuilt a 35 johnson - new pistons, bored out cylinders and all new gaskets etc...and also own a 55 (both late 70's models) so i consider myself semi-knowledgeable about these motors.

The bulb stays hard when it is pumped. I played with the motor yesterday evening and the bulb was still firm when i went out there just now. I've adjusted the low speed jet the standard 1 1/2 turns and then tried to tweak it as it idles, but i still get gas coming out. It doesn't squirt out it just slowly pools at the carb throat and dribbles down the side when enough gathers. There isn't a high speed needle on these, it's a fixed high speed jet.

Do you think a leaky bowl gasket could cause this? You know the main gasket between the two halfs of the carb? i can't tell if it's leaking or if it's just gas pooling from the throat of the carb. I'm also wondering if gas is leaking from the donut shaped gasket around the high speed jet tube.

 

[hidef]

Re: 6hp, 1974 fuel dripping out carb

It might be. You might need to buy a new rebuild kit and start all over again from scratch. Your float and needle valve are working if it holds pressure and I think you can rule out the gasket between the bowl and body. Did you miss a welch plug when you re-assembled it? Or not get one properly seated?

 

[scott_maier]

Re: 6hp, 1974 fuel dripping out carb

there is only one welch plug and i covered it completely with epoxy after seating it. I also put epoxy on the lead shot balls just for good measure. This is nuts...I'm gonna go try one more time before it gets to dark.

thanks for the suggestions

 

[AlTn]

Re: 6hp, 1974 fuel dripping out carb

rubber tipped needle valve?..the last couple of brp kits I bought have contained the old metal tipped needle so maybe the rubber tipped ones were having sealing problems?

 

[scott_maier]

Re: 6hp, 1974 fuel dripping out carb

rubber tipped needle valve?..the last couple of brp kits I bought have contained the old metal tipped needle so maybe the rubber tipped ones were having sealing problems?

yeah, i believe it is a rubber tipped needle, i think it is sealing though

Another weird thing happening is that the fuel leaking out has a brownish color to it. I know what your thinking...old gas, but it's not. I have cleaned/flushed out the 6 gallon tank,installed a new inline automobile fuel filter(i put it in front of the primer bulb) made of clear plastic so i can see the fuel, put new gas in and pumped the primer bulb until fresh fuel squirt out the fuel pump line(which was disconnected from the carb). And i previously drained the carb when i had it off the motor and dissembled. So the fuel leaking out should look bluish not brown. I'm wondering if the fuel is blowing back out the carb instead of leaking into the carb throat?? I took the intake manifold off last Saturday and checked the reed valves(again) and they looked fine.