Volvo AQ170A har starting

[blackhawkdc]

Hey all, I'm looking for some expert advice. I have a 1975 Chrysler Charger boat with a Volvo Penta AQ170A 6 cyl sterndrive powering it. It is very hard starting. It does not want to start or stay running until its popped enough times to get the engine somewhat warm. Ihave to pump the gas multiple times to get the engine to fire a few times and I have to repeat that procedure many times until the engine starts to get a little warm and as it warms up, it'll get better and better. Once I get it running and it starts to fully warm up, it seems to run great and will restart without touching a thing. I bought the boat last summer and have not had it out on the water, so I can not attest to engine power once warm. Seems to run really nice and idles smoothly once its warmed up.

Any ideas out there? Fuel? Ignition? PLugs are brand new, wires are good, cap and rotor are decent. Fuel is fresh, stabilized premium. how much fuel pressure should this engine have? I eliminated a choke problem, tri-carb engine with no chokes on the carbs. I noticed that when pumping the throttle, only the middle carb squirts a priming charge reliably.

Thanks in advance!

Seth

 

[blackhawkdc]

Re: Volvo AQ170A har starting

Anyone out there have some advice? Please?

Seth P

 

[bruceb58]

Re: Volvo AQ170A har starting

Have you ever tested the compression?

Also, maybe you aren't getting quite enough fuel from your priming circuit. have you ever tried pouring some gas down the carbs and trying to start it then? That is how I basically discovered my accel pump wasn't working well enough.

 

[blackhawkdc]

Re: Volvo AQ170A har starting

Have you ever tested the compression?

Also, maybe you aren't getting quite enough fuel from your priming circuit. have you ever tried pouring some gas down the carbs and trying to start it then? That is how I basically discovered my accel pump wasn't working well enough.

Bruce,
Thanks for the reply. All three carbs have fresh rebuilds in them, and yes, pooring fuel down the carbs will help it run. that's why I'm thinking Ihave a bad fuel pump. Like its not pumping enough fuel to supply all three carbs while the engine is cold.

Oh, and the compression is good. 120psi minimum across the board if my memory serves me right.

Thanks again,

Seth P

 

[Don S]

Re: Volvo AQ170A har starting

All the Volvo engines that use the Solex carbs rather 1,2 or 3 like you have no chokes and requier a lot of pumping and usually several attempts to keep them running when cold.
ALL the carbs should have working accelerator pumps. With only one working that will cause a real problem.
When first starting most also need to keep the rpms up around 1500 to keep running.
That 120 compression is really on the low side for those engines. Between 170 and 200 is normal.

 

[blackhawkdc]

Re: Volvo AQ170A har starting

Don,

Thanks for the response. I'll recheck my compression next chance I get. Seems to me that it was with in specs according to the service manual I have, so I didn't worry about it. Maybe 120 was a different engine I was working on last summer also. things just kinda meld together. I'll have to recheck it.

Any idea where I can get a fuel pump, or a rebuild kit? What about an electric conversion? What should the fuel pressure be?

Thanks,

Seth P

 

[Don S]

Re: Volvo AQ170A har starting

Who said anything about a fuel pump????
You need ACCELERATOR pumps, in the carbs, and clear passages in the carbs for them to worlk.

 

[blackhawkdc]

Re: Volvo AQ170A har starting

Don,

Sorry for not being 100% clear, but all three carbs have fresh rebuild kits in them, with rebuilt accelerator pumps. As stated in a previous post. Is there something else I need to be aware of with the accel pumps on these carbs? Ihave a full background in automotive work, including carbs, but maybe I'm missing something with these Solex carbs. Please educate me.

Seth P

 

[Starflight]

Re: Volvo AQ170A har starting

I'm w/ Don. it's not the pump.
I have the same carbs that had been rebuilt last yr. I found them intermittantly not squirting when pumping the throttle. I found the float needles sometimes sticking closed. I opened the tops of the carbs to find the bowls empty. I cleaned the needle valves and have been good to go.
If the pump is working well enough to fill 1 carb, it will fill them all if the float valve will let it.
pull the tops off the 2 that are not working and see if they are empty.