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aq130c low power or not much

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Leif Pickwell

New member
hi all, I have a 130c in a 19ft glass boat its all 1970ish rig, the problem is it seems low on power it takes a few hundred metres to get on the plane , all the electrics except coil were replaced, the compression is 3 at 150 and 1 at 130, i know they should be 170 would this make much over all difference of the power? any other ideas would be much appreciated, cheers
 
Low power can also be atributed to poor ignition advance.
Rusty flyweights that are not allowing any advance, or are limiting advance, can cause this.

When you check ignition timing, check more than just BASE advance.
You'll want to see if the progressive advance meets OEM specs.
If not, then there is part of your problem.... if not all of your problem.

With your OEM specs in hand, run the RPM up to near your full-in advance RPM.
Strobe your timing marks.
Jot down the progressive advance degrees in increments of 300-400 rpm, or so.
Plot this out in graph form.
Compare to your OEM specs.

You should see a linear curve of advancement up to the limit RPM.
At the limit RPM, you should see no further advancing.

You should also see no mechanical advance until above 900-1,000 rpm.... only BASE advance below this rpm.


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the problem is it seems low on power it takes a few hundred metres to get on the plane ,
Click to expand...

Ayuh,.... Has it Ever run right,..??

What Prop is on it,..??
It could just be Too Big a prop...
 
There could be many things contributing to the lack of performance. If the engine hasn't been run in several years, the compression readings don't mean much. They're low, but my 130 ran OK with those numbers. In a boat that old, there could very well be a considerable amount of extra weigh from waterlogged foam and wood. The extra weight will definately make the boat act sluggish. As others have asked, does it reach full RPM? Should be able to reach 5100. What is your maxwide open throttle (WOT) RPM and what speed are you seeing?
 
thanks for all the ideas, the timing did advance past 2000 rpmbut i didn't take any readings, when you rev the motor up it sounds good but still could be out i'm sure. I have no idea what seafoam is not sure we can get it in new zealand. I dont know the prop size but i would think it is ok i would not wnat to go any smaller as i need to be doing 4000rpm to keep it on the plane at 4400 it seems to cruise nice which is just shy of 20knots. i have not tried taking the revs past 4600 but will next time i take it out but last time with the extra people it would not rev past 3900 until i got up on the bow then it was fine when on the plane. any one know if trim tabs would help much?
 
Leif, free load revving won't tell us much, other than when checking the ignition advance.
Reason: the ignition on this engine is not dependant on any load.
IOW, the progressive advance will/should advance correctly even during RPM increase with no load on the engine.

I'd suggest that you test this with your strobe type timing light, or a digitally advancing light in Std Mode.
See where the advance is at/near the limit RPM, and in particular, see how it got there.
  • Was it one rather abrupt increase?
  • Or was it a linear curve while getting there?
I agree that ignition timing may not be what's causing this poor performance, but it can one item that you can check off of your P of E list.
It's all too often over-looked, and that's why I usually mention it.

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Leif,
I had this problem ,no matter what I did it would not pull the revs under load, it turned out to be the lobes on the cam worn
causing the valves to be open for to short a time.
 
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