AQ120 Engine cuts out 3/4 to full speed

[struluet]

Ok not sure if this is the problem or not about a year and a half ago we were fishing and the accelerator rod nut came off the rod . The boat been parked every since put it back to getter and and took it for a test run, now it runs good till you go 3/4 to full speed then run for a little bit then cuts out and stops. Is it the accelerator pump rod out of ajustment that is causeing this to happen or is it some thing else its not my fuel tank I am runing the boat off my kicker motor tank to make sure its not the gas in the tank. Thank you.

 

[Maclin]

Re: AQ120 Engine cuts out 3/4 to full speed

The accelerator pump in the carb is probably not the root of the problem you describe. It only pumps fuel out the squirters in the carb throat as the throttle is moved forward. Once the throttle stops moving the accelerator pump does nothing.

 

[struluet]

Re: AQ120 Engine cuts out 3/4 to full speed

ok thank you so would the fuel pump be the likely place to start .

 

[Don S]

Re: AQ120 Engine cuts out 3/4 to full speed

ok thank you so would the fuel pump be the likely place to start .

Do a pressure test on the pump, to find out, don't just go swapping parts unless they are bad.
Do you have a water separating fuel filter for your engine? IF not, you might want to consider installing one.
It could be the carb has water/corrosion/dirt in the carb partially plugging up the high speed passages,
You may also have boat fuel system problems. You can check them easily by running the engine off an outboard 6 gallon tank with new clean fuel in it, hooked directly to the fuel pump and see if you get full speed.

 

[struluet]

Re: AQ120 Engine cuts out 3/4 to full speed

the fuel pump seems to be working fine and has lots of fuel pumping out of it. I do have a water separating fuel filter and the carb was rebuild a year ago back in florida sent it to them because it was the only place I could fine the rebuild the jets that were needed to repair it. and I am using a 3 gal tank from my kicker motor to run the boat. still the same thing going on. could it have something to do with the oil presser sender unit cuting it off because of low oil presser at hight rpm, have read some post about that on your site . THANK YOU.

 

[Maclin]

Re: AQ120 Engine cuts out 3/4 to full speed

Strulet, your setup does not have that oil pressure sensing switch, your engine has a mechanical fuel pump. An oil pressure sensing switch is only used on electric fuel pump systems. On later models, when Volvos started getting electric fuel pumps, Volvo tended to go with getting power to the fuel pump from the alternator so even they do not have an oil pressure sensing switch that would cut off anything at higher rpms.

 

[Maclin]

Re: AQ120 Engine cuts out 3/4 to full speed

It does sound electrical in nature, if you mean the engine just stops dead and does not idle down and surge and sputter until it dies.

 

[struluet]

Re: AQ120 Engine cuts out 3/4 to full speed

Again Thank you . No it does slow down and then die"s It just sounds like its run out of gas but it does start right back up, so do you have any thing else, to help my on were to start to fine the problem . I'am lost. And I do want to thank you all for all the effort you all put out in trying to help me. maybe I should just pull the plug and let it die lo #2 Maclin Do you like salmon I have some smoked can salmon well send you some. Will be going fishing for them in about three weeks again. Email my your address at struluet@peak.org. no others need to reply Thank you.

 

[doggfather69]

Re: AQ120 Engine cuts out 3/4 to full speed

I have the same engine with a 270 outdrive. I have a very similar problem. I use to do just what you are saying so I paid it no mind. It seems that my points keep going out of setting. The problem is I have a spring or springs that have broke under the plate in the distributor. I plan to fix that soon. Your problem is definatly in the spark. When going over my wires I did find a short and that helped but didnt fix it. Ive done a total tune up on mine. I will update you on my fix soon!