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Need Help AQ151C runs roughdies on throttle up

A

Alan Brock

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"I have twin 1989 AQ151C's

"I have twin 1989 AQ151C's - Port engine is a little rough during warm up. Sometimes engine revs up and down during warm up. After the engine is warm, the engine will often die with a fast throttle-up. Have to pump the throttle a little to get it started and nurse it back up to rpm. I get an occasional backfire with a quick throttle-back. Symptoms are fairly consistent. Starboard engine runs like a champ (engines share common fuel flow). Houseboat installation - quick throttle adjustments are necessary for docking. No fun when one engine dies as I am nearing the slip. Any help would be greatly appreciated."
 
"I would start running a compr

"I would start running a compression test and afterwards verifying that both carbs are synchronized and with the idle mixture well adjusted. The procedure can be found in the operator's manual that you can download from Volvo's website.


http://www.volvo.com/volvopenta/global/en-gb/marineengines/older_engines_1/opera tors_manual/

Since the manual for the AQ151C is not available in English, you can follow the procedure for the AQ151A which has an identical carb layout as yours.

If the above does not solve the problem, then it will be time to start looking at carb cleaning/overhaul and ignition components."
 
Thanks for the quick response.

Thanks for the quick response. Will give this a shot next weekend.
 
I seem to have the same proble

I seem to have the same problem on my AQ125A. My guess is that the accelerator pump needs attention. If I play with he throttle when I add power it will take right off but a straight forward advance will cause a bog and a backfire thru the carb. If I grab the accelerator lever and pump it manualy it has no effect. I just replaced the timing belt and the timing is good so I know it's not that.

Time to read up on a carb rebuild I guess?

Steve P.
 
"However, you may want to make

"However, you may want to make sure first that the accelerator pump actuator in the carb is not sticking. If it does, a bit of WD40 or other penetrant oil should solve your problem."
 
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