1991 1800 Capri w/90 hp Force

[again]

I just bought the boat and took it out for a test run yesterday. With 650 lbs in the boat (3 people) the boat was sluggish on the holeshot and topped out at 32 mph. Winds were light (10 mph most). The boat has been sitting for at least a year, I put in new plugs, the linkage is adjusted correctly, I did not go thru the carbs. I put 10 gal premium fuel in it, some Berryman's, and Quick Silver oil. We only ran it for about 15 minutes (it was cold out there). I haven't verified the prop pitch.

So is this about the best I can expect from the motor or should it be performing better?

 

[azlakes]

Re: 1991 1800 Capri w/90 hp Force

... hello again,

yup ur within 5MPH, your running Premium Plus 2-Cycle TC-W3 Outboard Oil I take it? if you decarb your O/B, do a carb cleaning and look into re-prop you can get those mp's back. post over on the Force section of iboats and take a look at some of those threads. you'll get some great advice.


congrats and welcome

 

[again]

Re: 1991 1800 Capri w/90 hp Force

Thanks. The guy I bought it from claimed it would do 45 mph. He wouldn't lie to sell a boat, would he? I did find the prop pitch - 17. I'll read up on the Force secion. Thanks once more.

 

[Mark42]

Re: 1991 1800 Capri w/90 hp Force

Thanks. The guy I bought it from claimed it would do 45 mph. He wouldn't lie to sell a boat, would he? I did find the prop pitch - 17. I'll read up on the Force secion. Thanks once more.

I wouldn't be too discouraged. You wrote that you went out with about 650lbs in the boat, and that is a lot. It will probably do 45 with just you.

My 85 1600 Capri Cuddy w/85hp Force did about 40 mph with just me. It would do better with a fresher motor. With a full load it still high 30's.

Try taking it out solo and see how well it does.

 

[Bigprairie1]

Re: 1991 1800 Capri w/90 hp Force

Welcome to the forum...again.
I've got the exact same boat/motor combo just a year older (90'). The hull design is identical.
I don't have a GPS speed measurement of the boat, just speedo. That said, running a 17 pitch prop I was tickling about 42-43mph. With my other 15 pitch prop I was around 39-40mph.
The motor is in good condition with the compression all north of 125psi and seems to be in good/very good tune. Very reliable motor at this point.
I recommend you:
-check the compression on all (3) holes
-do some checks to see if you are carrying extra water in the hull and hopefully you haven't absorbed it into any of your floatation foam. I think this would add a lot of weight that would scrub a lot of speed off your boat.
Good luck and let us know how your checks go.
BP

 

[again]

Re: 1991 1800 Capri w/90 hp Force

I'm going to do the recarb and pull the carb bowls to see if there is varnish. I'll check compression as well.

My current prop is a 13.25 x 17 aluminum. I found where I can get a composite 4 blade prop for $86. Top speed is not important to me but a nice hole shot to get a skier up is. Do you think going to the 15 pitch composite 4 blade would help me out there?

 

[Mark42]

Re: 1991 1800 Capri w/90 hp Force

I'm going to do the recarb and pull the carb bowls to see if there is varnish. I'll check compression as well.

My current prop is a 13.25 x 17 aluminum. I found where I can get a composite 4 blade prop for $86. Top speed is not important to me but a nice hole shot to get a skier up is. Do you think going to the 15 pitch composite 4 blade would help me out there?

No doubt going down to a 15 pitch will get you moving quicker, especially with a load. But be careful, when I was under-propped on my 40hp Evinrude, on a hole shot the rev limiter would kick in because it was easy to over rev at WOT.

 

[khes142]

Re: 1991 1800 Capri w/90 hp Force

That might be all she wrote. my 86 16ft capri br with a 2002 johnson 90hp 4cyl will just hit 50mph with that load, and no wind or chop.

 

[again]

Re: 1991 1800 Capri w/90 hp Force

Will I did the decarb and ran it on the lake a week ago. There was no change. I added the SE 300 hydrofoil and took it out yesterday. That made all of the difference in the world. The hole shot is fine without changing the prop. The motor still doesn't sound like it turnings 5K RPMs so a tach is on the list to add. The boat runs like a top.

 

[Bigprairie1]

Re: 1991 1800 Capri w/90 hp Force

Will I did the decarb and ran it on the lake a week ago. There was no change. I added the SE 300 hydrofoil and took it out yesterday. That made all of the difference in the world. The hole shot is fine without changing the prop. The motor still doesn't sound like it turnings 5K RPMs so a tach is on the list to add. The boat runs like a top.

You might want to get out for a run with a GPS to get a more accurate speed measurement. You might have a little more top end than the speedo is indicating. The speedometers are generally not very accurate and definitely default to under-reading if they get plugged or if they are not all the way down in position.
For interest sake, you should do a quick compression test. This will give you an idea as to how much power is going to be realized put through to the prop. Even compression across all (3) cylinders is, of course, most important and ideally after that you want over 100psi all cylinders..and best...all north of 140psi.
After that the shortcomings would be just in the tuning and set-up I think.
The only thing that might slow the boat down is if you had extra water in the bilge or some water logged foam adding some unseen weight.
If you have a commercial scale near you, you might want to take the boat over it and see what kind of weight you are getting. I'm not sure but the whole package should be close to (or less than?) 2500lbs.
For improved tuning you want to post up in the Force/Chrysler area and Frank Acampora or one of the other excellent Force resources can help.
My two bits.
Good luck and keep us posted on the progress.
BP