Volvo 570a

[hien331]

Well took my boat out. While driving at low rpm ( at 1500to 2000), the engine sputters and was backfiring (well at least thats what the sound, sounds like)... Once we go a little higher, the sputter tends to go away and also the backfiring sound. And when steeriing, the steering wheel belt squeaks... I know I need to tighten that but would that cause the sputtering and the backfiring? Again I have a 1990 volvo penta 570a. I am not a mechanic and had a mechanic came to do some tune up and paid him quite a lot and told him stories of my boat and what it does... he didn't do anything but cost me money... Please help me out! Any recommendation to any good mechanics? I live in Orange County, California. Thanks in advance.

 

[Maclin]

Re: Volvo 570a

A squeaky slipping power steering belt will not cause those symptoms. Now if it was the alternator belt and the battery is really low it could cause low spark in the ignition. But I think the battery would be too low to even start it for it to be low enough to affect ignition.

When was the last full tuneup? Spark plugs, cap, rotor, maybe spark plug wires? Fuel/Water separating filter? How old is the fuel? When was the last time the carb was rebuilt?

I suspect it is a fuel quality or fuel delivery problem. The carb could need rebuilt if bad fuel has sat in it for a while. If there is water in the fuel the engine will not run very well at all.

 

[hien331]

Re: Volvo 570a

A squeaky slipping power steering belt will not cause those symptoms. Now if it was the alternator belt and the battery is really low it could cause low spark in the ignition. But I think the battery would be too low to even start it for it to be low enough to affect ignition.

When was the last full tuneup? Spark plugs, cap, rotor, maybe spark plug wires? Fuel/Water separating filter? How old is the fuel? When was the last time the carb was rebuilt?

I suspect it is a fuel quality or fuel delivery problem. The carb could need rebuilt if bad fuel has sat in it for a while. If there is water in the fuel the engine will not run very well at all.

Engine oil, fuel filter, oil filter, fuel seperator,and water pump,a cleaned out the carb was changed a month ago. Cap, rotor, thermostat, spark plug wires was changed in June of 2008. Spark plug wasn't change because it was hard to get to ( i know that was stupid of me but I couldn't get to it without having the special tools or a modifed tools). Thats why I had this so called 30 years experience mechanic to do but he couldn't do it. Any feedbacks again will be greatly appreciated!

 

[Maclin]

Re: Volvo 570a

Did it run like this it right after the tune up work? Or did it run ok for a few trips them start acting like this?

Fouled spark plug(s) can act like that. So can a carb fuel delivery problem or lean condition. Also a bad spakrplug wire can do that because the spark plug eventually fouls.

I read where you put on a lot of new parts but if they were not installed properly, like breaking a spark plug wire terninal, or the carb was not rebuilt well then you will have more symptoms than what you were trying to cure.

Regarding the spark plug that you cannot get to, I bet the exhaust manifold is interfering. I can get most of mine out with a socket but one or 2 of them I have to get creative with. I only use the socket to tighten or loosen, I get it off the plug as soon as I can, and not try to back it all the way in or out with the socket on it, I do that by hand. You should also try a 13/16" (I think that is the size) open end or boxend wrench on the sparkplug(s) you cannot reach with a socket.

 

[Maclin]

Re: Volvo 570a

You should probably have a compression check done now as a diagnostic. Some of the problems you describe can also be due to burnt or otherwise bad intake or exhaust valves. A compression check will show the helath of your engine, and also tell you if a proper tuneup can help at all.

 

[hien331]

Re: Volvo 570a

Did it run like this it right after the tune up work? Or did it run ok for a few trips them start acting like this?

Fouled spark plug(s) can act like that. So can a carb fuel delivery problem or lean condition. Also a bad spakrplug wire can do that because the spark plug eventually fouls.

I read where you put on a lot of new parts but if they were not installed properly, like breaking a spark plug wire terninal, or the carb was not rebuilt well then you will have more symptoms than what you were trying to cure.

Regarding the spark plug that you cannot get to, I bet the exhaust manifold is interfering. I can get most of mine out with a socket but one or 2 of them I have to get creative with. I only use the socket to tighten or loosen, I get it off the plug as soon as I can, and not try to back it all the way in or out with the socket on it, I do that by hand. You should also try a 13/16" (I think that is the size) open end or boxend wrench on the sparkplug(s) you cannot reach with a socket.

Before the tune up... boat ran better but it did sputterred and backfired but not as nearly bad when the tune up was previously done. Also, on my previous post I post that I had a leak in my outdrive, can this be the cause of it too? The reason I am asking all of this newbie questiions is because I am trying to get a mechanic down and instead of a mechanic trying to BS and rip me off, I'll have a little knowledge of what should be done. Your help has been very helpful! If there's anything else I should know, please educate me! Thanks Again!