backfire at 3000rpm on just rebuild aq125a 1988

[rock&reel]

just got to rebuild my aq125a volvopenta 1988 it star really good but, when i try to go fast, i can go no more than 9knots per hour, or same as 3000 rpm and start backfiring when i just get the engine from machine shop. time was bad so we fix it, but the engine time suposed to be at 10". if we put at ten it will no star or i star it will shake much, so we put the time on zero an stared right away but right now we can go no more than ten knots, because star backfiring can someone help me on this please? thankyou

 

[Clyts328]

Re: backfire at 3000rpm on just rebuild aq125a 1988

Rock&Reel, I have a 2000 #5.7Gsi 280 and it started backfiring at around 3000 rpm also. I had repair shop look at it and found out that head gasket was gone.
Hope this helps.

 

[dirtyoldman]

Re: backfire at 3000rpm on just rebuild aq125a 1988

I am a little confused about what you are saying.

If you had a hard time getting the timing set properly or couldn't get enough adjustment at the distributor, you may have the distributor gear on there wrong. It's also possible that the valve timing is off because of an improper timing chain installation.

Do you know how to check camshaft timing?

 

[rock&reel]

Re: backfire at 3000rpm on just rebuild aq125a 1988

thanks for your response but i just rebuild the complete engine & this was the first time i took it to the water after i rebuild the engine thanks

 

[rock&reel]

Re: backfire at 3000rpm on just rebuild aq125a 1988

no i dont know how to check camshaft timing. thanks for your response

 

[rock&reel]

Re: backfire at 3000rpm on just rebuild aq125a 1988

i will explaing better the time when i just got the rebuild motor from the shop it was really hard to stared, so i took the boat to my car mechanic & he find the distriburetor was one dent passed so he moved that dent back, it now started right away, but when i tested on water at 30 rpm it stared the backfire so no more than 9kts thank nyou