1984 AQ125A Will Not Start.

[heathstallings]

I have a 1984 Bayliner Capri with a Volvo Penta AQ125A and a 270 outdrive. It will not start. The engine was running great on friday. I start it up on saturday and all seems fine until I accelerate to wide open throttle. Once the rpms reach about 4500, the engine began to slow down to about 2800 rpms (throttle lever still at wide open). Boat ran great at the lower rpm. I noticed that the temperature was a little warmer than usual. It has typicall stayed about 180, but was hovering around 200 this time. The outside temperature was alittle warmer than it has been recently, so this could be the cause for that. After cruising a short distance, it backfired as I decelerated to come to a stop. After about 2 hours, I restarted the engine, but had to give it about 1/3 throttle to get it to start (not usually the case). Engine started, but ran rough for a few seconds and then died. It restarted using the same 1/3 throttle technique, but again ran rough and died instantly as I put it in gear. That was the last it has run. It will not start or even attempt to. I have tried starting fluid and checked the fuel flow, but still no change. I pulled the plugs. They looked a little dirty, but not bad. I replaced them just to be safe, but still nothing. The engine had a full tune up around September. I am at a dead end here. I have fuel and spark, but am unsure how to proceed.

 

[captmello]

Re: 1984 AQ125A Will Not Start.

Have you checked the timing belt?

 

[heathstallings]

Re: 1984 AQ125A Will Not Start.

The belt looks good. It is less than 1 year old. As far as the timing itself, I don't know. Do you think it is a timing issue? If so, how do I go about checking it?

 

[heathstallings]

Re: 1984 AQ125A Will Not Start.

I just spoke with my father in law about this. He said it could be the coil. He said that if the coil isn't working properly, the plugs may not be able to handle the fuel being dumped in. I removed a plug and checked for spark. I am getting some spark, but not sure if it is as it should be. I don't know if the coil is a viable option, but at this point I will take any advice.

 

[captmello]

Re: 1984 AQ125A Will Not Start.

I'm not sure about the coil theory...

you need a timing light to check the timing, its easy to check. How about the fuel? could it have water in it? How many times did you run the boat since the tune up? Just for the heck of it, check to make sure the distibuter isn't loose. try to turn it with your hand.

 

[heathstallings]

Re: 1984 AQ125A Will Not Start.

I have run it about 10-15 hours since tune up. The fuel is fresh and I have a water separating filter installed. I used starting fluid and there was no change, so I'm pretty sure it isnt a fuel issue. Distributor is tight. I have read thet the timing belt could slip a few notches. Is there a way to check it without a timing light? If not, how do I check it with the timing light?

 

[Don S]

Re: 1984 AQ125A Will Not Start.

While it is possible the coil is bad, everybody always blames the coil first thing, then after replacing it, they still have the same problem.

You need to do some troubleshooting first, than fix what is bad. Do you have spark from the coil? I mean a bright blue spark that will snap a half inch gap?

 

[captmello]

Re: 1984 AQ125A Will Not Start.

The timing belt slipping may or may not effect the ignition timing, which is timing I'm referring to. It depends on which gear may be out of time. However, checking the timing is with a light is easy, but if you've never done it...Perhaps you know someone with a light and a little know how that can give you a hand. If it is the timing belt, it is not a difficult replacement, again for someone with a bit of experience.
If you have a friend with a timing light, he may have a compression check gauge. Have him bring that as well. low compression is a sign of a slipped belt as well.

Or I could be steering you in the wrong direction completely, but the timing check and compression check would be my next moves.

 

[heathstallings]

Re: 1984 AQ125A Will Not Start.

There is spark from the coil, but it is more of a yellow or white color. As for the timing light, I would have to buy one. I don't have anyone that is familiar with them. I am fairly mechanically inclined, but have never dealt with timing.

 

[heathstallings]

Re: 1984 AQ125A Will Not Start.

Ok. I have changed the coil. Cleaned and adjusted the points. I verified proper voltage to the coil. I checked the spark from the coil with a spark tester and still have a thin orange spark. I guess my next step will be new points, capacitor, and rotor. No one in town has parts available, so I had to order. Should have them wednesday or thursday.

 

[heathstallings]

Re: 1984 AQ125A Will Not Start.

Parts came in today. I replaced the capacitor, points, and rotor. STILL NOTHING!!! It acted as if it wanted to start once, but did not. I still have an orange spark from the coil. Should there absolutely be a blue spark from the coil? Any ideas???

 

[captmello]

Re: 1984 AQ125A Will Not Start.

The belt looks good. It is less than 1 year old. As far as the timing itself, I don't know. Do you think it is a timing issue? If so, how do I go about checking it?

Are you referring to the v-belt on the front of the motor or the toothed timing belt which is buried behind the timing cover?

 

[Don S]

Re: 1984 AQ125A Will Not Start.

Timing won't cause week yellow spark. Low voltage to the coil can do it, have you check the voltage to the + terminal on the coil? It should be near battery voltage. You also need a fully charged battery with tight terminals. Not just a weak battery that can barely turn the motor over. It could also be a defective coil. Have you checked the resistances on the coil and compared them to specs?

 

[heathstallings]

Re: 1984 AQ125A Will Not Start.

Got it started today. The timing belt slipped several notches at the distributor. I removed the belt and lined up all three timing marks. I reinstalled the belt and JACKPOT!!! It appears the timing belt tensioner will need to be replaced. I have one ordered and hope to be on the water again soon. As for the weak spark...still there. I have 12.5 volts at the coil with the key on and 10 volts while the engine turns over. The coil, points, condenser, and rotor are brand new. Perhaps the spark is sufficient even if it isn't exactly ideal.

 

[Nickypoo]

Re: 1984 AQ125A Will Not Start.

Even if the tensioner is 100% functional, the belt will still slip if that nut that locks the tensioner down comes loose. Use lock-tite on that nut when you replace the tensioner.

 

[captmello]

Re: 1984 AQ125A Will Not Start.

Good to hear you got it running. Now, do yourself a favor and set the points using a dwell meter, followed by setting the timing using a timing light. Both are simple and do not take long, but have a huge effect on engine performance.

 

[heathstallings]

Re: 1984 AQ125A Will Not Start.

I have dwell meter ordered. I have done some reading on how to set it here in the forums. Seems fairly straightforward. A guy I work with has a timing light. Thanks for the advice.