Volvo penta 4.3 flooding

[Vendi1986]

Hi,

I have problem with my volvo 4.3 engine. Carburetor is constantly flooding. I have bought 2 new rebuild kits and changed every gasket, PV, needles. Everything is cleaned and float is adjusted properly. It is 2 bbl Demon carburetor. I have tested float and there's no air leaking ( turned upside down and blow in fuel inlet). Fuel pump tested and has 5.5 psi. I have removed fuel pump and filter and also carburetor, connected together at my garage and there was no issues with flooding. Is there anything else I could check and what could be cause of flooding? It has electrical pump and choke...

 

[alldodge]

Which needle does the carb have, the one with or without the spring tip? If it has the spring tip as part of the needle the float needs to be lowered slightly.
Is the 5.5psi read while the motor was running or benched tested?

 

[Vendi1986]

Hi,

It's needle and seat. There's no spring in it. I even tried to lower the float and still it's flooding. I have tested fuel pump at home... It was running for about 20 seconds. Fuel pressure is constantly 5.5.

 

[alldodge]

Nothing wrong with pressure
Being a VP it should be a Holley carb

https://www.holley.com/blog/post/how_to_fix_a_carburetor_that_floods/

 

[Vendi1986]

I can take it apart and show you float and everything you want. It's written on the bowl Demon even holly gaskets are exactly the same but I ordered demon set also because of PV and needle\seat

 

[Vendi1986]

 

[Vendi1986]

I was thinking of changing oil. Maybe it mixed oil and fuel and it backfires. Sorry my english is not that good.

 

[alldodge]

Putting oil in gas will make it smoke some but unless there is a lot of oil it would still run

I has to have something to do with the needle and seat. You said have tried twice, but its still the only thing that keeps fuel from over flowing. That is unless your pressure gauge is off and its actually higher then 5.5 psi

 

[Vendi1986]

I didn't mix oil and gas. I thought gas itself mixed with oil because of flooding.

I believe that human can blow more than 5 psi. Used also air compressor and there's no air inside of the bowl. Luckily I have spare low pressure pump brandnew and tested it... Same thing happens. First start after checking carburetor last for about 10 seconds and it floods. After that it's impossible to start unless I give it a little bit of throttle or by itself on carburetor. If I rev it on high rpm it works for few seconds and dies. Every time before dying it floods. I removed spark plugs, bought new, started motor without plugs for 5 seconds. Put new and same thing happens. I've read that it can be alternator or bad oil pressure sensor. Alternator is ok. Oil pressure is also ok, I have shortened wires to see if it will work and same thing happens.

 

[Scott Danforth]

you may have a franken carb or you may have a Demon 2-barrel that someone swapped in.

however VP's originally came with holley. the 2-barrel is a 2300 (half the 4150)

 

[Vendi1986]

you may have a franken carb or you may have a Demon 2-barrel that someone swapped in.

however VP's originally came with holley. the 2-barrel is a 2300 (half the 4150)

I really doubt that it can be problem because I drove that boat for last 2 seasons with same carburetor and everything was fine.

 

[Lou C]

Are you sure that the float is not rubbing against the float bowl somehow, bent float arm, etc?

 

[Vendi1986]

Float is bent so it can get less fuel in the bowl. Arm itself is intact. As I said before, in my workshop it's not flooding. Only when it's mounted on engine.

 

[Lou C]

What about the float absorbing gas?

 

[Vendi1986]

I'm sorry but I really don't know what you mean by that. I can disassemble carburetor tomorrow and post photos here if that will help

 

[Scott Danforth]

float setting is accomplished by gland nut on top of bowl and checking sight glass openings

 

[Vendi1986]

float setting is accomplished by gland nut on top of bowl and checking sight glass openings

I understand that more you screw needle and seat, float goes down meaning less fuel in the bowl. If I turn bowl upside down, float/needle is closing. There's no air leaking inside

 

[alldodge]

Flooding is either the needle valve or float.
Just like a full bucket of water, if ya open the valve and more water runs in the bucket, it will over flow. If valve shuts off then no overflow

If you have a brass float and its leaking then fuel starts filling up the float and it will sink and allow more fuel in. If you have a brass float, it can be shook and you can hear and feel gas slosh around inside the float

If you have a plastic float, it might have soaked up fuel but would need to weight it to see if its heavier then new

 

[Vendi1986]

Flooding is either the needle valve or float.
Just like a full bucket of water, if ya open the valve and more water runs in the bucket, it will over flow. If valve shuts off then no overflow

If you have a brass float and its leaking then fuel starts filling up the float and it will sink and allow more fuel in. If you have a brass float, it can be shook and you can hear and feel gas slosh around inside the float

If you have a plastic float, it might have soaked up fuel but would need to weight it to see if its heavier then new

Thank you for info. I will check float and luckily I have new one, I'll try to replace it and let you know.

 

[Scott Danforth]

A blown power valve will also cause a motor to run pig rich