young gun seeking advice on bayliner aq125a/270 outdrive. want to go faster...

[fortunate son fishing]

my boat maxes out at about 18-21mph depending on fishing 3-4 people(after getting my trim tabs in working order again). my tach took a crap so im not sure on my rpms running wide open. last summer i went from a 15x15 prop to a 14x15 and she seems to pop up out of the water better but i still would like to hit 25 mph. i have a 15x17 prop off craigslist for $25 but its opposite roation than what im set up for. according to my serloc book it sounds like an easy switch over. but my crew insists on looking for a 6cyl motor. any suggestions on props or spark plugs possibly getting the head shaved .025''? seems like i can do some mods before looking to a new motor.

i got into helping my buddy set up a 4cyl race car we shaved the head and it did wonders. went from placing 6-8th to 1-3rd in the main event without engine troubles.
i have a background in motocross and know changing gear ratios, valves, cams and a few other tricks help performance. so im curious as to doing the same with my aq125a.

any suggestions are welcome. would like to keep it less than $2,000.

 

[fortunate son fishing]

Re: young gun seeking advice on bayliner aq125a/270 outdrive. want to go faster...

at the beginning of last summer we installed a hot start kit, someone mentioned a dual carb set up, just not sure what to do i guess.

 

[Bondo]

Re: young gun seeking advice on bayliner aq125a/270 outdrive. want to go faster...

my boat maxes out at about 18-21mph depending on fishing 3-4 people(after getting my trim tabs in working order again). my tach took a crap so im not sure on my rpms running wide open. last summer i went from a 15x15 prop to a 14x15 and she seems to pop up out of the water better but i still would like to hit 25 mph. i have a 15x17 prop off craigslist for $25 but its opposite roation than what im set up for. according to my serloc book it sounds like an easy switch over. but my crew insists on looking for a 6cyl motor. any suggestions on props or spark plugs possibly getting the head shaved .025''? seems like i can do some mods before looking to a new motor.

i got into helping my buddy set up a 4cyl race car we shaved the head and it did wonders. went from placing 6-8th to 1-3rd in the main event without engine troubles.
i have a background in motocross and know changing gear ratios, valves, cams and a few other tricks help performance. so im curious as to doing the same with my aq125a.

any suggestions are welcome. would like to keep it less than $2,000.

Ayuh,... Welcome Aboard,...
If yer a Motorhead, ya oughta know that ya can't trick out a motor, without knowin' what it's Doin'....

1st order of business is gettin' a Workin' Tach...

Besides tunin' it to proper factory specs, I doubt yer gonna get anymore real, usable horsepower outa that little motor...

A compression test will give ya an Idea of the motors general Health,...

Shavin' the head don't do any good, with weak rings...

 

[RogersJetboat454]

Re: young gun seeking advice on bayliner aq125a/270 outdrive. want to go faster...

+1^^^^

To add to that, make sure the distributor is holding proper time (timing mark isn't "bouncing" when checking the timing with a light), the timing belt has been replaced recently, and all other maintenance is up to snuff.

Going with the Volvo dual carb set-up may help a little. All the other stuff you mention works wonders in cars, but not so much with boats.

 

[Brucetafer]

Re: young gun seeking advice on bayliner aq125a/270 outdrive. want to go faster...

amen, ive looked like crazy for options and such for more power, but in these 4 bangers, especially being Swedish motors, theres not many options for parts without lots of custom crazy swede stuff... I took my boat to a Volvo race tech and he said that the motors we have are a gold mine if we want to sell them to race car builders, the cam is worth a ton!... also, he said unless you want to blow around 2500-4000 bucks for a full build, balance, fuel injection system (NOT RECOOMMENDED AT ALL ON BOATS!!!) youd see the same HP as a v6 Volvo (GM BLOCK) which if im not mistaken, mounts directly to our outdrives...

 

[Maclin]

Re: young gun seeking advice on bayliner aq125a/270 outdrive. want to go faster...

Might take another look at the advice given to "this guy" a while back...

http://forums.iboats.com/volvo-pent...-outdrive-please-help-525561.html#post3563592



If you were in Sweden I would recommned looking these guys up even though they started with a different VP engine....

Ockelbo T17DL Supercharged part1 - YouTube


I know at 22 it is hard to do, but just take what this one gives and learn to love it, put all that money you would spend on engine upgrades into a piggy bank and keep your eye out for another boat

p.s. I bet somone out there will think your boat's performance is just fine and hand over a check someday!

 

[beermak]

Re: young gun seeking advice on bayliner aq125a/270 outdrive. want to go faster...

First get ur tach in working conditions. you must know ur WOT before doing any change in props.

Then which bayliner we are talking? If its underpowered its more likelly ull have to swap for a 6cyl insted of spending any on ur actual engine.

but first, tach and test its WOT to proceed.

 

[RogersJetboat454]

Re: young gun seeking advice on bayliner aq125a/270 outdrive. want to go faster...

Keep in mind that putting in a 6 cylinder engine isn't going to be a simple drop and swap affair.

For starters, the drive ratio will be wrong for a 6 cylinder, but the fun only starts there.
The in-line 6 Volvo should be avoided. Not that it's a bad engine (I maintain one), but parts are scarce and big $$$ when found.
If you were to go with a Chevy V6, you run into all sort's of other fitment issues. For starters (and Don may be able to confirm this), I believe the Chevy V6 was never offered with a 200 series drive. Theoretically, you may be able to fit one, since the flywheel cover is the same pattern as a Chevy V8. Then you would need to figure out motor mounts, cooling system, manifolds, etc. A complete, and potentially expensive cobble job in other words.

You could go with an entire later style drive package, but the hole in the transom would be too big, and both the inside and outside of the transom would need to be rebuilt to correctly install the drive.

In short... there's no easy way to upgrade what you have other than buying another boat with what you want...

 

[Zanderman]

I found in my searches for performance parts, that the AQ140A head with the dual carbs will match the AQ125A block. There is the addition of some oil cooler components if using the 140 cam. Under 2000 by the right people. Suggested increase of 10 plus hp. I would suggest verifying that with a Volvo marine mechanic, but I have seen that posted a few times on different boating community sites.

 

[Zanderman]

I have seen all the parts required for this on EBay recently.

 

[MikDee]

Zanderman, Just wanted to let you know this is a 17month old thread!

 

[dennis461]

Can't quote anymore?

 

[500dollar744ti]

How big is your boat, if it has got trim tabs, I'm imagining a bigger boat that's underpowered in the first place? I race volvos with these engines (in cars) and I am very familiar with them. You can build yours up a little but in all honestly, for a boat, it's going to be cheaper and more reliable to swap a chevy v6. Don't worry about the gear ratio for now, if you are pushing a 15p prop now you can compensate the gear ratio with a propeller and see how you do before changing the drive.

AQ125a is a b21 I believe and that limits your options compared to having a b23. I could build a reliable b23 with 180hp but it would require sourcing some very hard to find parts probably not be worth it when a chevy v6 will make more power out of the box and require no hard to find parts.

On your b21, your best bet is do the dual carbs and get a cam for starters, that will help you free up some power without breaking the engine down. Might be able to get a little bit out of an adjustable cam gear as well.

So, start with dual carbs and report back, then I can help you from there.

 

[Maclin]

The original poster has another boat now with a V8.

 

[PiratePast40]

The original poster has another boat now with a V8.

I love a story with a happy ending!