19' Bayliner Capri AQ125A/270 - What prop?

[Dr. Velocity]

I've got an '82 19' Bayliner Capri with a (probably very tired) Volvo 4 cylinder AQ125A engine and 270 stern drive. Last time out on the water, the boat would do around 33 mph @ 4500 RPM. However, that prop is now at the bottom of the lake, so I have no idea what size and pitch it was (if I had to guess, I'd say either 14 x 17 or 14 x 19).

So, what size/pitch prop is recommended for this setup? I'll probably pick up two props on eBay (one as an emergency spare), so a range of sizes wouldn't hurt either.

 

[mickjetblue]

Re: 19' Bayliner Capri AQ125A/270 - What prop?

I have an '85 Capri with the AQ131A 4 cylinder, and was using a 14 x 19.
I decided to try the spare I had, which is a 14 x 21. The improvement was
very significant, with faster out-of-the-hole response, better control, and even
a higher top end with lower rpm planing at about 3100rpm now. Gas mileage is still good.
I won't go back to the 14 x 19, but will keep it as a spare. Good luck.
I found the engine performs great when the ignition parts are kept clean, and
the points gapped right.
Question - how is your idle speed steering? Maybe some wandering back and forth?

 

[steelespike]

Re: 19' Bayliner Capri AQ125A/270 - What prop?

I have an '85 Capri with the AQ131A 4 cylinder, and was using a 14 x 19.
I decided to try the spare I had, which is a 14 x 21. The improvement was
very significant, with faster out-of-the-hole response, better control, and even
a higher top end with lower rpm planing at about 3100rpm now. Gas mileage is still good.
I won't go back to the 14 x 19, but will keep it as a spare. Good luck.
I found the engine performs great when the ignition parts are kept clean, and
the points gapped right.
Question - how is your idle speed steering? Maybe some wandering back and forth?

Not an expert but:: I'm surprised at your performance going up to a 21" normally you would get a decrease in hole shot performance.Your wot rpm is really low.Your motor needs to operate within its recommended range.probably around 4,000+.
Your 19" would only give you about 3,500 rpm.It seems something is up.
Perhaps you need to check your tach.
As far as slow speed wander that is normal on an i/O, smart tabs help hole shot and wander.

 

[mickjetblue]

Re: 19' Bayliner Capri AQ125A/270 - What prop?

I don't think I was clear in the way I worded my rpms. Now, with the 21, I am cruising comfortably at about 3100rpm, where with the 19 I had to keep it at about 3300rpm. When I'm cruising at 4,000rpm, now I am going about 35 mph,
and that is faster than before when I had the 19 prop on. Top rpm is about 4500+, although I haven't really pushed to get the top. The speed in the high end of the rpms doesn't really change much more than 35mph.
I think I'm going to install a stabilizer over the prop to help overall. I installed a whale tail stabilizer on my 90hp Merc outboard(1st boat), and that made a major improvement on hole shot, overall speed, control, and gas mileage.
I hope it will help on the low speed wander. Also looking at smart tabs.
Thanks for the feedback.

 

[rndn]

Re: 19' Bayliner Capri AQ125A/270 - What prop?

Stay awau from the added stabilizer. They place undo stress on your lower unit. If you feel you need one then you really need smart tabs. Don't be fooled by the advertising and low price of the stabilizers. Virtually everyone on this forum will agree with this assessment.