Tuning Problems (AQ125B)

[JFrog]

Hey Guys,

Hopefully I'm not becoming annoying yet...lol!

Anyway, finally got everything running pretty good, but now have two new symptoms plus a possible third.

1. When reving up the boat it seems to rev just fine, but if I leave the boat at a higher rpm than idle and keep it at that number, it slowly begins to die out. I've noticed that it is burning alot of fuel!
2. After shut down, when I restart, it will backfire the first time, then start when I try again.
3. It seems like I might have fuel getting to the exhaust. (See rainbow fluid in the fresh water bucket I'm using)

What I've done so far: rebuilt the carb, set the plug gaps and set the point gap. Set the idle and adjusting screws to manual specs. I haven't set the dwell or timing just yet.

I had a similar problem with my 62 Ford Galaxie. I had fuel pouring out of the exahust manifolds with the original holly carb. I purchased a brand new edelbrock carb for it and now it runs like a champ.

Anyway:
Could this simply be a dwell and timing issue?
Is my carb flooding out the engine?
Do I just need a new carb?
Anything else I'm missing?

Thanks,
Keith

 

[Don S]

Re: Tuning Problems (AQ125B)

Could this simply be a dwell and timing issue?

It could, everything has to work together. If your spark isn't good enough to burn the fuel..............

Is my carb flooding out the engine?

Very possible.

Do I just need a new carb?

Probably not. I would sure rebuild it first and make sure it's all clean and adjusted right inside.

 

[JFrog]

Re: Tuning Problems (AQ125B)

Well, I've already re-built the carb. New gasket set and cleaned everything. The only thing I didn't replace was the pump diaghram because it looked good.

I'll go ahead and get the dwell and timing set.

I've noticed though that the pdf file owners manual for this motor dosn't have the dwell angle.

Where would I find that?

Thanks,
Keith

 

[Don S]

Re: Tuning Problems (AQ125B)

Odd the didn't put that in there. It's in here AQ125,145 A,B Service Manual.pdf - 4shared.com - document sharing - download - Don S

 

[JFrog]

Re: Tuning Problems (AQ125B)

Hmm, strange, when I went to view the file, it only showed from page 1-8. Do you have another link Don?

Thanks,
Keith

 

[Don S]

Re: Tuning Problems (AQ125B)

That's the only link, try redownloading. I just tried it and all 74 pages download fine.

 

[JFrog]

Re: Tuning Problems (AQ125B)

Found the problem, needed to sign up with 4 shared

 

[Don S]

Re: Tuning Problems (AQ125B)

Must be something new. Never had too before.

 

[JFrog]

Re: Tuning Problems (AQ125B)

Well, I think I found the information I need but I want to double check with you since timing is pretty new to me. The terminology is what is getting me.

Anyway:

1. What's refered to as the cam angle in the manual is the dwell angle, correct?
2. The 32-35 degree btdc is what I am going for with the timing light at 4200 rpm, correct?
3. How is the dwell angle adjusted?

Thanks,
Keith

 

[Don S]

Re: Tuning Problems (AQ125B)

1. What's refered to as the cam angle in the manual is the dwell angle, correct?

Yes, that is the dwell.

2. The 32-35 degree btdc is what I am going for with the timing light at 4200 rpm, correct?

No, set it at idle rpm and just check the advance timing.

3. How is the dwell angle adjusted?

Adjusting the point gap is how you change the dwell angle.

 

[JFrog]

Re: Tuning Problems (AQ125B)

Got it, thanks Don.

I was wondering: if the dwell is set with the point gap, why do we set the point gap with a feeler gauge to start? Is it just to get it in the ballpark so that setting the dwell is a bit easier?

Thanks,
Keith

 

[Don S]

Re: Tuning Problems (AQ125B)

Gap is used to get close, so you can get it running and check the dwell. The Volvo rubber band engines (OHC engines with timing belts) like to have the dwell at 62? or 63? for best running and best starting.
I used a analog dwell meter while cranking the engine with the cap and rotor off and reading the dwell while cranking. You will have to learn your meter, as you may have to set the dwell at something other than the desired to get the 62 or 63 when running.
I had to set points 5? high on my meter. Just takes practice.

 

[JFrog]

Re: Tuning Problems (AQ125B)

Ah, that makes sense.
I suppose though, if done your way, the gap wouldn't have to be set first since you don't rely on the engine actually firing up. It seems that would be much easier because you don't have to constantly take the cap and rotor off each time you get a reading and need to make an adjustment.
Anyway, I'm looking forward to trying this out. I will be using a dwell meter and timing light for the first time on this project!

Thanks,
Keith

 

[JFrog]

Re: Tuning Problems (AQ125B)

This seems a bit strange to me.

According to the owners manual the idle should be set to 900 rpm.

However, in the service manual, under the "basic setting", it says to have the rpm at 750 for timing which needs to be at 6 degrees.

Correct me if I'm wrong here, but when the manual says "basic setting", isn't it refering to idle? If so, why would you have two different idle speeds?

Thanks,
Keith

 

[Don S]

Re: Tuning Problems (AQ125B)

Set the timing at 750 rpm, it has mechanical advance which is why it needs to be slower. Then set the idle rpm to specs for normal use.

 

[JFrog]

Re: Tuning Problems (AQ125B)

Ah, got it.

Alright, so I go ahead and set the dwell to 62 plus or minus 3 degrees, then set the timing at 6 degrees at 750 rpm idle speed, then re-set the idle speed to 900 rpm?

Thanks,
Keith