83 Volvo Penta 270 prop questions

[triplehooked]

I recently purchased an 83 Bayliner Capri 1950 with the AQ125A engine and 270 outdrive. The po claims it will go 35-40mph but I think that is pushing it. The first time out on the water the prop was slipping, so I had to pick up another. I found a used prop at a local shop and the fella gave me a 14x18 aluminum three blade. I'm concerned that this is a little too much prop, but the PO was paying for it so I didn't complain. I will primarily be using the boat for tubing with a family of 6, so I figure the load to be close to the max of 8 people/1200lbs. Will this prop be too much? I was originally thinking a 14x15 but the shop didn't have any used. I don't know the rpm's of the motor with this prop as I haven't tried it yet. I don't want to be lugging the motor....

Question #2 What gear ratio is this outdrive? And how do you break the serial #'s down?
Here are the part #s

Engine AQ125A 7679010468
Transmission 850676 8302 241624
Outdrive PZ NR 27113361 D


As always, thanks a bunch for your time!!

Travis

 

[captmello]

Re: 83 Volvo Penta 270 prop questions

Its all about WOT RPM. You should be getting close to 5000 rpm at wot. The rest is prop talk.

Your outdrive should be 2.15:1 ratio.

 

[triplehooked]

Re: 83 Volvo Penta 270 prop questions

I was finally able to make it out with the family today. With everyone on board it we maxed out right at 4300 rpm's and about 32mph. Of course with two tubes in tow I kept it at 20mph. It looks to me like I have some room for a prop change. What pitch do you folks recommend for another prop? It's always good to have a spare! I'll be staying with an aluminum three blade.

 

[valleyfield]

Re: 83 Volvo Penta 270 prop questions

I was finally able to make it out with the family today. With everyone on board it we maxed out right at 4300 rpm's and about 32mph. Of course with two tubes in tow I kept it at 20mph. It looks to me like I have some room for a prop change. What pitch do you folks recommend for another prop? It's always good to have a spare! I'll be staying with an aluminum three blade.

hello all, on my side i got a 19 feet bayliner capri 1985 with a volvo AQ125B and 270 unit and my propeller is 14/17 with 3 adultes, my max speed is 29 mph at 4500 rpm and my wot is 5100 rpm and i try a 14/15 propeller, my speed almost the same and my wot 5300 rpm and more, so my best propeller 14/15 but for skying is 14/15.

thx

 

[am_dew]

Re: 83 Volvo Penta 270 prop questions

I was finally able to make it out with the family today. With everyone on board it we maxed out right at 4300 rpm's and about 32mph. Of course with two tubes in tow I kept it at 20mph. It looks to me like I have some room for a prop change. What pitch do you folks recommend for another prop? It's always good to have a spare! I'll be staying with an aluminum three blade.

Your WOT rpm's are a little on the low side but you also have a max loaded boat so you have to also take that into account. If you went to a 14x15 prop, your WOT rpm would probably raise by 800-1000 rpm, which is too high for your engine. You could try a 14x17 which would probably raise your WOT rpm to around 4600 as well as give you a little better hole shot performance at the sacrifice of a little top end speed. Generally speaking, when your increase pitch, you get a decrease in WOT rpms and hole shot performance, but you will gain faster top end speed. The opposite is true if you lower the pitch.

 

[rscholar]

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[Gone Postal]

Re: 83 Volvo Penta 270 prop questions

I have an 82 Capri, AQ125A Volvo Penta 270. My WOT is about 4600 (2 adults about400 LBS ). I have a 14 X 19. Tops out 35 - 40. Does that right. Thanks guys.

 

[Tommywalton]

Re: 83 Volvo Penta 270 prop questions

Ive got the same boat. I run a 15 x17. For towing. The 270 cant trim while underway. A serious drawback if you want some speed .

 

[Gone Postal]

Re: 83 Volvo Penta 270 prop questions

Like I stated on my 82 Capri I just got it used this week with a 14x19. Should I try a 14x17. What is the pro and con. Thanks I know this is a redirect. Powered by a aq125a w/ Volvo penta 270.

 

[am_dew]

Re: 83 Volvo Penta 270 prop questions

Like I stated on my 82 Capri I just got it used this week with a 14x19. Should I try a 14x17. What is the pro and con. Thanks I know this is a redirect. Powered by a aq125a w/ Volvo penta 270.

You'll get approx. 300-400 more WOT RPM, better hole shot and quicker planing with a 14x17. The con is that you will lose a few MPH at the top end. Which prop would be best would likely be determined by how you use the boat most often...if you do a lot of tubing, skiing, etc. and want a quicker hole shot and/or you have a heavy passenger load, the 14x17 may be better. On the other hand, if you want a higher mph with a lower RPM (ie. cruising) and are OK with the way the boat gets up on plane, the 14x19 would probably be best. I used to run a 14x17 on my 17' runabout with a Volvo AQ130C but I was always having to watch the tach to be sure I was not going over the recommended WOT RPM. I got a 14x19 and my WOT RPMs dropped into the "safe zone" while my top speed increased by 3-4 MPH. I am cruising almost all the time so the 14x19 is perfect for my boat and engine.