1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

rigasr · Aug 24, 2011

I have a very standard 1999 Bayliner Capri 1800 (18ft) with 120HP Force outboard which I bought used about 3 years ago.
It has a stainless steel prop (13 1/4 x 15), not sure if this is standard though when it shipped from factory.

I am just not sure I am getting the performance that I should be getting from this boat. Just me alone on it with a full tank of gas I get just over 30mph at close to 5000 RPM. With wife and 2 kids it drops to about 26MPH. When I do sharp turns and circles, power/speed drops drastically. Pulling a tube with kids on, drops to about 25MPH.

To me it feels like the motor is lacking power but then again, I am not sure. Trying to get an idea from folks on this BB on what speed/RPMs I should be getting for this type of boat.

Thanks

foodfisher · Aug 24, 2011

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

Wot could be a little higher, not much (5500). Don't know prop variations. First thing I would do is check compression.

fucawi · Aug 25, 2011

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

The prop does sound a bit small in pitch to me for the size of the motor ..my 115 yamaha had a 20 pitch BUT if its doing 5000 its not far out for the engine power...Checking compression is the easy way to see if you have a problem

jerryjerry05 · Aug 25, 2011

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

Forces come standard with an aluminum prop.That boat should have at least a 19p.
The stainless 15 is equivalent to an aluminum 17p
The stainless was added later.
To optimize performance???BASICS! First do a compression test. Then a spark test.Just to be sure!!!
You sure the tach is right? Tiny tach,add to the system.
The speedo right? A handheld GPS??
The prop you have probably used for pulling tubes/boards.
If the comp/spark is good.I'd start with an alum 15pitch.
They have a prop section here with some good people answering there.

Living in the mountains? At higher elevations the carbs need to be re-jetted.
If the boat came from the flatlands and move to the mountains,you might need to re-jet.J

anple · Aug 25, 2011

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

I have a 17' Maxum with 97 Force 120. I use 21p aluminum prop. It could do 50 at WOT.

rigasr · Aug 26, 2011

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

The timing, compression and sparks test good. I am in Colorado at about 6000ft altitude. Not sure though that the cards are jetted right, how can I tell? As mentioned I have a 13 1/4 x 15 stainless steel prop and get about 5000RPMs at full throttle. Engine has recently been decarbed and carbs have been tuned as per FAQ on this BB as well as timing.
Are you saying I should try a bigger prop? If so, wont that cause the motor to struggle more?

Jiggz · Aug 26, 2011

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

Well at 5000 RPM at WOT, the engine is about normal although others will tell you it should be at 5500 RPM but the RPM rating at WOT is actually between 4500 and 5500. I'll say try a higher pitch prop. I've got stainless 13.25" 17p and at 4500 RPM will do 35 MPH with 4 people on board and will do 40 mph at 5000 RPM. In fact, I'm thinking about upgrading to try a 13" 21P except I'm just waiting for the right price on ebay or CL! does anybody has this prop I can borrow for about a week just to try and see if I'll see improvement and maybe just decide to buy a new one off iboat? I'll pay the shipping.

jerryjerry05 · Aug 26, 2011

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

What are the comp #s? All plugs burning right?
You absolutly positive the prop is 15P?
Any higher will drop the RPMs more. A 15 al. will bring them up.
Any history on the boat.Where is it from?
The standard jet at sea level is .088 and it runs down with higher altitude.4000-6000 is .082
above 6000 is .080
Pop one of the carbs off and get the main jet out and see what's engraved on the side.

Go to outboardignition.com has test procedure for outboards.
Some stators will go bad and not deliver power after 4000rpm.

rigasr · Aug 28, 2011

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

Compressions area all between 115 - 125.
I'm not sure what you mean by if all plugs are burning right. They all spark blue if that's what you mean.
The prop is for sure 15p. It has a big stamp on it with this size parameter (13 1/4 x 15).
No history on this boat unfortuantly, bought it from someone in Denver 3 years ago who didnt know much about boats. Not that I know much either.
I'll prolly not mess with it much this season and leave as is. Before I winterize I'll remove a carb and check the jet sizes.

Thanks again.

fucawi · Aug 29, 2011

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

for approx speed in mph double the pitch 2 x 15 = 30 and 80% of that so about 26-27 mph.....(engine 6000 and 2 :1 gearbox)

if your revs is 5000 and you go to 17p your revs will drop to 4600 ..what you gain in pitch you loose in rpm

jerryjerry05 · Aug 29, 2011

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

15stainless and 17al will give about the same rpms.

nonnie · Sep 16, 2011

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

I have the same setup ('99 Bayliner 1802 with '99 Force 120) I run a 13x19 Michigan Wheel Vortex alum. prop. I get 5100 rpm and the boat runs like a rocket. According to the Force service manual rpm range on the engine should be 4750-5200. Bayliner shipped the boat with a 13x19 Mercury Black Max prop.

labawg · Sep 16, 2011

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

FYI at 6000 feet your performance will be ten to twenty percent less than at or near sea level. I suspect your propeller is the correct pitch. A higher pitch (17P) may improve your top end but maybe a little doggie at the hole shot.

rigasr · Sep 17, 2011

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

Nonnie, when you say it runs like a rocket, what true MPH are you getting? Also where are you located at?

billme2 · Jun 29, 2012

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

rigasr said:
Nonnie, when you say it runs like a rocket, what true MPH are you getting? Also where are you located at?

Habe you figured it out yet?
I agree on the prop not being right
I have the same boat it hits 43mph with 3 in boat and half tank.
In Illinois

jerryjerry05 · Jul 1, 2012

Re: 1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

billme 2 the post is 10months old.
You should start your own??

1999 Bayliner Capri 1800 with 120HP Force outboard - performance question

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