4.3 Volvo penta carburetor

[Luisbr]

Hey guys I just have a problem,I have a 2000 190hp 4.3 Volvo penta it was running like crap back firing a couple of weeks ago so I disaited to ribuilt carb (2barrow Holley) and it was very dirty,clean it ready good rebuild and put back in the boat,I back off the air needles 1.5 turn to start,I play with this carb for some time and I Ended up putting air needles almost all the way in,right now there 1/2 of turn out which it shouldn't be enough air but it work pretty good no back firing and it adle good,I figure I have a intake leak so I spray card cleaner all over intake,hoses,and carb but nothing,the boat runs good but is lacking power on wot I think it needs more fuel but if I open air needles it gets too rich and start smoking the spark plugs,not sure if I have a bad carb I checked timing and is good,I'm pretty sure is carburetor but not sure what lol I put 90 gas in it,no hesitation but still not enough power at WOT,checked compression and is 150 psi in all cylinders coo,any help will be appropriate thank u

 

[itsathepete]

If you had an intake leak it would cause it to run lean, not rich like you describe. Did you verify the float was set to the correct height, and that the needle valve was not leaking? The mixture screws are fuel screws not air screws. Opening them allows more fuel causing it to run richer.
Your compression is good. Make sure your distributor cap and rotor and spark plugs are clean and you have good clean connections on all ignition wiring. Corrosion can cause ignition issues that mimic fuel problems. Make sure you have clean fuel with new filter. Do all the basic tests then come back to the carburetor if you can't figure it out.

 

[dubs283]

1/2 turn out on a Holley (which I'm guessing you have) isn't uncommon for idle/air mix. As stated those control fuel, not air and only at idle speed.

When was the last full tune up, with fuel filters?

 

[Luisbr]

If you had an intake leak it would cause it to run lean, not rich like you describe. Did you verify the float was set to the correct height, and that the needle valve was not leaking? The mixture screws are fuel screws not air screws. Opening them allows more fuel causing it to run richer.
Your compression is good. Make sure your distributor cap and rotor and spark plugs are clean and you have good clean connections on all ignition wiring. Corrosion can cause ignition issues that mimic fuel problems. Make sure you have clean fuel with new filter. Do all the basic tests then come back to the carburetor if you can't figure it out.

Hi thanks for replying,I though the same think and I check the float yesterday and it’s good I check everything else since I was there and all looks good and when I bought the carb kit I got new cap,rotor,spark plugs and wires since I never change them when I bought the boat 4 years ago and they look like It need it to be change,put new gas 90 and I replaced the fuel filter a week ago it even have a new coil since the other one rusted away,I’m going to check timing again and vacuum if u can think of anything else let me know thank you

 

[Luisbr]

1/2 turn out on a Holley (which I'm guessing you have) isn't uncommon for idle/air mix. As stated those control fuel, not air and only at idle speed.

When was the last full tune up, with fuel filters?

Thanks for replaying I really though there were in to much but I guess not and I did change cap rotor spark plugs wires and I change the fuel filter a week ago I even got a new coil the other one works but it was rusted off,I’ll check timing and vacuum and see what I get