Volvo Penta 4.3 Hard Starting when warm and backfiring. Please Help.

[brad1313]

Hi, We had our boat in the mechanics a couple weeks ago because it was backfiring a lot, they diagnosed low and high pressure and changed both of those. Couple weeks it was fine and now, it starts fine when cold but really struggles once it's warm. Cranks for 10 seconds doesn't start, after about 5-6 attempts it starts, Also at about 2000-3000rpm it backfires (just the once). If you increase throttle slowly over time doesn't seem to backfire.

Additionally, seems to burn through oil fast, don't think this is related.

It's my bosses boat but can get more info for anyone. Thanks in advance for your help.

Brad

 

[alldodge]

Its a 4.3 what, model number (GL, Gi, GXi, GS, etc)?

Its not good to be burning thru oil

Also sounds like the mechanic doesn't know what there doing, hope with more info, my opinion will change

 

[Bondo]

Ayuh,....... Welcome Aboard,...... Backfirin' is usually from a Lean condition,.....

Has anybody examined the contents of the fuel filter for anything but clean fresh gasoline,..??

 

[brad1313]

Hi, thanks for the swift responses.

It's a Gi I've been told. Boss reckons it burns through about half a litre/quart every 7 or so hours. Which seems crazy to me.

I wasn't hugely impressed with the mechanics as we took it back twice and they finally changed both pumps. I'll enquire about the contents of the fuel filter, I'm not sure it has been checked out. What would we be looking for, oil? water? or just anything that's not supposed to be there?

 

[alldodge]

or just anything that's not supposed to be there?

Anything other then clean gas

The Gi uses throttle body injection and the backfiring is from the motor not getting enough fuel (lean condition). Since the pumps have just been replaced, I would start as Bondo mentioned the fuel filter. Then check fuel pressure from idle and up thru the full rpm band.

Probably have a restriction, antisiphon valve, fuel line, fuel tank pick up tube

 

[brad1313]

Thanks very much,

Going to see about changing the fuel filter. We are unsure whether the mechanic changed the lower fuel pump when he said he did a year ago. I'll get to work in the next couple of days and let you guys know/ask for more help!

Cheers