Volvo Penta AQ145A Project

[capnmatt]

I purchased a project boat that i am working on. It is a Wellcraft 250 Coastal with 2 Volvo Penta AQ145A engines. One engine is missing from the boat (I have collected almost an entirely new motor in my garage that i am just starting to build. The other motor is in the boat but i had to rebuild the top end. Sometime in the past someone added an electronic ignition module to it - so the condenser and points are gone.


So here are my main set of questions. The coil is not getting any power. It looks like the main power source that powers the coil is direct from the alternator (or is it possibly a voltage regulator mounted on the alternator??) it puts out 0.9 volts. I see an in-line resistor. The electronic ignition is connected to the coil as well along with a while wire that looks like it is for the tach. this white wire is connected on the negative side.

i disconnected the wire leading to the alternator and connected a 12v line direct to the battery. When i do this the engine will run, sputter, and die. i am not able to give it any gas or it will die.

i installed new plugs. the carbs are getting fuel. when the engine is running the timing is to manufacturer specs.

i do not know how the coil is supposed to be wired. I am wondering if i am overloading the coil? (It gets VERY hot) from what i can tell it is a Bosch coil with a 3 ohm internal resistor. (If i did the resistance test correctly)

PLUS - i don't understand how there isn't a + wire attached to the coil fed from the ignition switch?? Is this somehow supposed to be controlled from the wire leading from the alternator to the coil?

I'm also wondering if i have issues with the carbs / fuel / adequate fuel pressure. when i open the carbs the front solex carb's accelerator pump squirts gas but the back carb does not. otherwise both carb fuel chambers are filling with gas.

so for starters - Does anyone know how this coil set up is SUPPOSED to be wired?

thanks
matt

 

[alldodge]

:welcome: to iboats

I'll start with your last question; below is how a distributor with points should be wired. The coil gets a full 12V while engine is cranking, but once started the power goes through a resistor to the coil. Note: this is for a car not a boat (vacuum advance not present on a boat)


The above wiring is simplistic and not exactly how connections are made on your motor. Power feeding the coil does not and should not come from the alternator. Electronic ignition will use straight 12V all the time during cranking and running. Electronic ignition uses a different coil with an internal resistor built into the coil. If your using the coil designed for points and no resistor it will get hot and will burn out over time.

Power feeding electronic ignition should come in via the key switch.

 

[capnmatt]

Hi. thank you SOOO much for your reply. I wired the coil directly to the ignition switch and disconnected the coil from the alternator. i fed the carbs with a can of fresh gas, changed out the wires and spark plugs. The motor has been sitting presumably for years so i also replaced the impeller. I cleaned out the carbs with two cans of carb cleaner. Both carbs now "spit" gas into the barrels when i give it throttle. The motor will start but it doesn't want to stay running. I had to advance the timing for it to run at all. The engine will only run if i am constantly moving the throttle. It will want to die out and i can give it full throttle. The engine will not rev too high... once it picks up rpms i lower the throttle. I can keep the motor running for a few minutes by exercising the throttle, but eventually no matter how hard i try it dies out. so i am thinking:

1) Carburetors need to be rebuilt
2) fuel pump not providing enough pressure
3) on-going ignition problems
4) vacuum leaks

What are your thoughts?? I am starting to get more familiar with this motor - but i still don't see where there are any vacuum ports. I don't even know where to hookup my vacuum gauge as i might be able to diagnose.

thanks Matt

 

[alldodge]

Howdy Matt
You say the motor has carbs, as in more then one carb. Is it more then one carb?
From having to pump the throttle this tells me it's not getting enough fuel. Lack of fuel is either, bad fuel pump, incorrect or dirty carb, fuel filter restriction, fuel pick up in the tank or restriction in the line. Not running for eight years I would start by replacing filters in line and in the inlet fitting of the carb. Next thing I would rebuild or replace the carb

 

[capnmatt]

Hi. Yes the motor has two Solex 1 barrel carburetors. I agree with you. I think i will work on rebuilding the carbs, and a new fuel pump for starters. I was hesitant rebuilding them as i don't have any experience syncing carburetors once they are rebuilt but i guess it is time to learn something new.

 

[capnmatt]

One more question: since i'm replacing the fuel pump ---what are the thoughts on going low pressure electric with a regulator?? they are roughly the same price as the mechanical ones. Or am i better off sticking with the OEM mechanical???