How To Increase Your Rpm On Force 85 Hp?

[happykiforever]

Please help. i just bought the bayliner capri 85 force was built in 1989. My boat is really slow. it planes around 30 MPH max. Is there any adjustment to increase the rpm so it can run faster. i have read on some forums the max speed for capri 85 HP is around 40 MPH averagely. Thanks alot

 

[notsunkyet]

Re: How To Increase Your Rpm On Force 85 Hp?

well it depends.. the 85 is not a blow you shorts off powerhouse off the line. A different prop will help that but youll loose top end. have ya done a good tune up, decarb and time it?
the bays of that time were for skiing and playing around not for setting land speed records.
40 is about all your gonna get but that is with the boat empty, no foam in it and one person .... makes it kinda tough but they are fun.
I have asked many on here if i can stick a bigger motot but according to Frank amcorpora(?) he is like a know everything guy and does know everything! he said in my post over in, force outboards, that it would take a motor of 2x the hp to make a 10 mph difference.... the problem is the hull design.
if ya hop over to the Force outboards, and look for a post that has (Frank Amacorpora mostly , or anyone else who wants to chime in) and read that.It may help

 

[roscoe]

Re: How To Increase Your Rpm On Force 85 Hp?

i have read on some forums the max speed for capri 85 HP is around 40 MPH averagely. Thanks alot

Depends what size Capri. They were made from 14' to 20' in length.

You MIGHT get 40 mph out of an 85 on a Capri 16' or 17'

 

[Dave K.]

Re: How To Increase Your Rpm On Force 85 Hp?

+1 Roscoe..I have a 16' cuddy w/ all kinds of "stuff" on the boat. Maxes out 36-37.

 

[sho3boater]

Re: How To Increase Your Rpm On Force 85 Hp?

I have a '83 capri 16', I did everything to it I could after putting a new transom in. It had a SS 19p MI wheel prop I sharpened up. Took everything out of the boat I could. It still has the foam in the floor because I didn't want to tear the seat bases out. I put drains in and one side had some water. Anyway I got 43 gps out of it at near 6K rpm, too high. I had the prop thinned and more cup and now it runs 5300-5400 on my new tach, before I had a clamp on test tach. That is still the same 41-43gps depending on weather, and speedo says like 48 or so.

It wants to dip the bow so I straightened the pad some and put trim on the strakes to help keep the bow dry. Still runs flat, was thinking of putting a jack on it but then I need to change the steering cable that barely fits now and not had time to find the stuff I need for that. Also the block has been replaced so likely it does not have that many hours on it. Motor is raised near an inch on the transom, it will cavitate if I trim it way up and holeshot, but it gets up really fast that way. Sometimes it wants to porpoise a little at higher speeds with trim way up and at top speed the last few degrees of trim make no difference. One thing that gives a mph or so is synthetic gear lube. I changed the timing and it didn't help, but you can damage the motor that way I ran premium that time and advanced it, but put it back.

About all I can do is take the floor out and put knees and stringers in, take all the foam out or replace. Put lighter seats in, the jack, and if I can get a good prop on it maybe it I'd see 5mph but I'm not sure about that. I tried a merc 20p laser 2 and it would not pull it at all, it only went 36gps. But that prop needs to have the motor higher to work right so I'm not surprised. Still with a jack I don't think it would pull it without making the boat lighter. The pad is not that bad if you can keep the bow up, but the faster it goes the lower the bow drops. I think it is coming off the center strakes they have a big hook in them, think that is where the porpoise comes from. I sanded those down a little too and it was better, but the bow dropped a little too. I have a jack, water pressure gauge, but no time to do all that yet. I even sanded the pad and LU.

 

[jerryjerry05]

Re: How To Increase Your Rpm On Force 85 Hp?

Depends on prop,RPM ,load etc.Do a compression test.Set the carbs.
Put in 1/2 tank of fuel 2 adults ,cooler then run it and check RPM at WOT.
Get a hand held GPS .Post your results.J

 

[jkust]

Re: How To Increase Your Rpm On Force 85 Hp?

I have an 84 sixteen foot capri with the 85 and it is a blast to run. We get a few clicks over 40 on gps totally stock. It wasn't offered with a tach when we bought it new in 1984 so never knew the rpm's. The prop is alum and I can't recall the pitch off hand but think it is a 17. Must be about the lightest 16 foot fiberglass bowrider I have ever been in so really moves well for what it is. It just tips the scale dry a hair over 1000lbs. I am not sure what 0-30 time is on it but I am sure it is faster than my sig boat but just a little less stable.

 

[happykiforever]

Re: How To Increase Your Rpm On Force 85 Hp?

I just clean the carb and it is just so hard to get it started. i had to use the starting fluid. i used to run 30 mph and now it runs only 20 mph. i also adjusted the carb linkgage and thought i could make it run faster.
i just could not make it start easier and run faster.
Thank you so much for your help.
God bless

 

[NYBo]

Re: How To Increase Your Rpm On Force 85 Hp?

Starting ether is a bad idea in a 2-stroke- no lubricating properties.

DO you have a service manual? There is clearly something wrong with the motor and/or prop for such a dramatic speed decrease, and you need to start with the basics: spark plugs, timing (including advance), compression, carb setup, etc.