Volvo-Penta AQ 125a/270 with trouble under load

[jerryjerry05]

Re: Volvo-Penta AQ 125a/270 with trouble under load

MHO/The Volvos run best with VOLVO props.There is something about the size of the blades
I had a friend who asked me to look at his boat.It just wasn't performing the way it should be.Wouldn't get up to speed or RPM.I checked everything!!!! Nothing could be found.
As I was wraping up my tools I noticed a brand new Michigan wheel and asked how long it had been on the boat and how long it was acting up.Took off the Mi wheel and put the Volvo back on and it was the problem.
Those 125's don't have the umph to act like a big boat.Try the Volvo prop.J

 

[farmdoc]

Re: Volvo-Penta AQ 125a/270 with trouble under load

Will post pics after this weekend. Also get pics of motor mount, i have seen it mentioned in other posts.

Will update this post after I get prop and get boat back in water, will do compression test as well.

Understand that a volvo was designed for a volvo prop, but my wallet wasn't right now.

After I am happy with the dependability, then I will spend the money on the prop, but it is an extra $150 that needs to go to engine right now.

Understand 125 is small motor, but the CV-18 is a small boat, I imagine the power to weight ratio is fairly decent. My Dad's Rinker 230 Fiesta had a V8 but was 5 ft longer and twice the size. So it is all relative.

Anyway, I appreciate all of the help and suggestions I have gotten, will update in a few days/week once I get back to it.

John

 

[farmdoc]

Re: Volvo-Penta AQ 125a/270 with trouble under load

OK, It has been a year, but some family issues caused me to stop boating early last year.

Update: I need to correct, it is an AQ 125B, not a.

So, winterized and put up last fall. Memorial day, turned it over and ran good out of water. Stuck it in and same problem as last year, maybe get 2000 rpm and lots of backfiring, etc.

Only thing left on fuel side was to replace pump, which I had on hand so that is in. Put in new plugs and a new distributor cap, still same problem (maybe improved to 2400 rpm).

Started messing with timing. I didn't mention this last year, but the firing order the previous owner had was 1-2-3-4, which is wrong according to my manual. Long story short, timing had been set 180' out. Switched the #1 plug to the opposite side of the cap, plugged wires order, 1-4-3-2 (may have a typo, did it per the book though) and she fired right up. This was a 'static' timing, engine not on, rotate crank while a light was hooked to ground and low voltage wire on distributor.

Took it out and ran her up to 4900 rpm, best yet.

Still doesn't like throttle open for long above 4000, accelerates decent but after a while - 20-30 seconds, starts losing power. Throttle back down to 25-3000 rpm and smooth.

I think I need a timing light and need to time correctly while on. Also, Set at 6' BTDC now as my manual stated (went with 10 last year).

Newest problem, one episode of overheating with my son on a knee board. Had the equivalent of 3 adults on boat and him in water. Put a new impeller in last spring but didn't run it much. Could it harden that quick? Should I do a back flush of sea water and coolant on it? What other causes are there to overheating on these models? I am also thinking the thermostat probably needs replaced.

Always welcome for ideas. Next post will be a pic of her at the dock.

 

[Don S]

Re: Volvo-Penta AQ 125a/270 with trouble under load

Firing order should be 1-3-4-2 Rotor turns clockwise.

You also need a dwell meter to set the points. The dwell should be at 62 or 63? for best running, THEN you can set your timing to spec.

 

[farmdoc]

Re: Volvo-Penta AQ 125b/270 with trouble under load

Re: Volvo-Penta AQ 125b/270 with trouble under load

Don S: Thanks, i will do that (of course now I have to teach myself what that is and how to do it...I think I read somewhere on here you have posted a few how tos!)

I will be heading to river again in 2 weeks so will have my auto shop buddies give me a quick lesson, pick up a dwell meter and a timing light and be all set.

Yes, I do have order as 1-3-4-2, just had a minor brain lapse in last post. Wife says it happens often.

Thanks for the help!

 

[-JR-]

Re: Volvo-Penta AQ 125a/270 with trouble under load

Not sure if you fixed it yet.
This might help.
This has happened to my boat also ,engine will only idle and boggs down if you open up the trottle.
What I found was a small jet screw fell out of the cab .
Do not have the manual in front of me for the name of the jet , but it was located upper front of carb It does not have a spring under it like a idle air jet screw.
Hopfully this helps

 

[farmdoc]

Re: Volvo-Penta AQ 125a/270 with trouble under load

JR, will check that as well. Will be working on it this weekend. First dwell, timing light, cylindar compression, then move to carb (I think that's the right order - ignition first, then fuel/carb system).

 

[Maityme]

Re: Volvo-Penta AQ 125a/270 with trouble under load

OK, It has been a year, but some family issues caused me to stop boating early last year.

Update: I need to correct, it is an AQ 125B, not a.

So, winterized and put up last fall. Memorial day, turned it over and ran good out of water. Stuck it in and same problem as last year, maybe get 2000 rpm and lots of backfiring, etc.

Only thing left on fuel side was to replace pump, which I had on hand so that is in. Put in new plugs and a new distributor cap, still same problem (maybe improved to 2400 rpm).

Started messing with timing. I didn't mention this last year, but the firing order the previous owner had was 1-2-3-4, which is wrong according to my manual. Long story short, timing had been set 180' out. Switched the #1 plug to the opposite side of the cap, plugged wires order, 1-4-3-2 (may have a typo, did it per the book though) and she fired right up. This was a 'static' timing, engine not on, rotate crank while a light was hooked to ground and low voltage wire on distributor.

Took it out and ran her up to 4900 rpm, best yet.

Still doesn't like throttle open for long above 4000, accelerates decent but after a while - 20-30 seconds, starts losing power. Throttle back down to 25-3000 rpm and smooth.

I think I need a timing light and need to time correctly while on. Also, Set at 6' BTDC now as my manual stated (went with 10 last year).

Newest problem, one episode of overheating with my son on a knee board. Had the equivalent of 3 adults on boat and him in water. Put a new impeller in last spring but didn't run it much. Could it harden that quick? Should I do a back flush of sea water and coolant on it? What other causes are there to overheating on these models? I am also thinking the thermostat probably needs replaced.

Always welcome for ideas. Next post will be a pic of her at the dock.

I have the same engine and setup that you have, just a bigger boat. I had the same problems with engine under a load (In the water). I found that my points were shot. Instead of using points again, I replaced the points with Electronic Ignition (Pertronix Ignitor Part#2842 - Cost $83.00 and a Pertronix Flame Thrower Coil Part# 40611. cost 32.95). The install was easy, took about 30 minutes. The engine has never run better since I have owned the boat.

 

[farmdoc]

Re: Volvo-Penta AQ 125a/270 with trouble under load

Some good news: This weekend, set dwell (was at 74, have it down to just below 64). Then completed timing...is 30+ degrees before top dead center too much advance? Had done timing statically previously, for $12 at Harbor freight, purchased an induction timing light and now have it at 6 BTDC.

I will need to work on carb some more, idle rpm would change from one run to the next (varied by about 200 rpm max from 900 rpm Saturday afternoon to 700 when warmed up on Sunday morning).

All in all very pleased. Ran all the kids on the knee board (biggest one is 160lbs), no issues, engine was smooth and stayed right at 180 degrees. Still not getting max rpm. Will get up to 4500+ after a few seconds, starts to lose rpm and power, no backfiring though. If I keep at 4000 rpm or less, runs smooth.

I am a beginner shade tree mechanic so not sure, but I am thinking carb adjustment, maybe needs a valve job? Ignition and fuel are good so what else is there?

Thanks for all of the help.

 

[Mullin]

Re: Volvo-Penta AQ 125a/270 with trouble under load

10? BTDC 0?12.5 r/s (0?750 r/m)
36? BTD 70 r/s (4200 r/m)

30+ degrees before top dead center too much advance?

I listed the stats from the book above. So at 4200 rpm in gear, you should have 36? of advance. You can tie off your boat to the dock really well and check it.

Still not getting max rpm.

Could just need a prop with a smaller pitch.

Will get up to 4500+ after a few seconds, starts to lose rpm and power

That's kinda weird though. I'd suspect a weak coil (really cheap guess) or lack of fuel pressure at that rpm. Pressure is really low for these carbs (2-4psi)though it can be checked.

 

[farmdoc]

Re: Volvo-Penta AQ 125a/270 with trouble under load

Again, Thanks for everyones help. Was doing a little work on the trailer, trying to figure out why tilt mechanism not working. Well, because it is seized completely. Where would you guys recommend I look for a decent used mechanism? Are there any reputable boat engine 'junkyards' in the USA? I have no idea where to start.

Thanks

 

[sqbtr]

Re: Volvo-Penta AQ 125a/270 with trouble under load

Does the motor on the tilt run?

 

[farmdoc]

Re: Volvo-Penta AQ 125a/270 with trouble under load

Does the motor on the tilt run?

Motor does not run.

 

[sqbtr]

Re: Volvo-Penta AQ 125a/270 with trouble under load

Do the relays click? There are two sources of power in the system. One for the coil side of the relay, one for the load.

The units are very expensive and it will likely be cheaper to fix what you have.

 

[farmdoc]

Re: Volvo-Penta AQ 125a/270 with trouble under load

sqbtr, thanks. Of course it is at the river so I won't mess with it again until the weekend. My brother in law does a little electrical work so I will have hime dig in to see what needs replaced vs rebuilt. Will update this weekend on what we find.

Thanks again!

 

[farmdoc]

Re: Volvo-Penta AQ 125a/270 with trouble under load

Quick update, pulled the lift, shaft was bent, did get it to extend and retract a little so relay and motor still work. Sealed off hole and put on project list for winter.

Of course, went to put boat in and play and.....nothing. Starter solenoid shot. Took it to a local guy and he has it rebuilt and should be good to go this weekend, complete rebuild, $100.