'88 Force 85hp low top speed?

[88capri]

Hey all,

I have an 1988 Bayliner Capri 18' with a 1988 Force 85hp outboard engine. First boat, first time on lake with family (400lbs people and supplies) and we topped out at 30mph, and were cruising at 25mph. These numbers were off the speedo on the boat, not GPS but felt like we were going slower. Ill get a GPS reading this weekend. The motor sounds strong nothing out of the ordinary, just felt a little slow.
My reference being my brothers 1998 Capri Classic quite a bit more HP on the same size hull, and ALOT faster 35mph+. End point here I suppose is, am I being picky and want more than I can get from this motor or is the MPH a good reason to have it looked at?

 

[tater76]

Re: '88 Force 85hp low top speed?

30-35mph is about what my 85hp pushes my old tri-hull fully loaded with 12 gallons of fuel, 2 adults, one kid, cooler, and misc gear on flat calm water. It really depends on your prop, load in the boat, trim, water conditions, etc. Try playing with the trim, and swapping props with different pitches to get the performance you want.

 

[SkiDad]

Re: '88 Force 85hp low top speed?

when you GPS it also let us know your RPM. Also the pitch of your prop - you might need to drop down a few pitches to push that heavy of a boat with an 85.

 

[88capri]

Re: '88 Force 85hp low top speed?

I don't have a tach, is there another way to track RPM, is it difficult to install one? I'm running a 13x17 prop

 

[SkiDad]

Re: '88 Force 85hp low top speed?

I think you have the right prop and you're about maxed mph. I get about 38 with the family aboard. Normally there is a 125 on an 18'

 

[NYBo]

Re: '88 Force 85hp low top speed?

No such beast as an 18' 1988 Capri. They are 17' and 19' (actually a couple of inches shy); the 17' came with the 85 HP (ask me how I know )

 

[Jiggz]

Re: '88 Force 85hp low top speed?

There are many factors that can affect WOT speed. Trim, loading, and water conditions to name just a few. The best thing to do is to do a one man test for WOT speed while checking for different trim settings.

 

[jerryjerry05]

Re: '88 Force 85hp low top speed?

Do a compression/spark test.
NYBo said it.
The boat/motor combo is probably a 17 the 19 came standard with a 125.
You should be going faster. I drove a 17/85 and it did almost 35+
Post a pic?

 

[88capri]

Re: '88 Force 85hp low top speed?

Thanks for the correction! I thought they were 17'6" I was rounding up! :facepalm:

 

[88capri]

Re: '88 Force 85hp low top speed?

Do a compression/spark test.
NYBo said it.
The boat/motor combo is probably a 17 the 19 came standard with a 125.
You should be going faster. I drove a 17/85 and it did almost 35+
Post a pic?

How do I do a compression/spark test? Or do I take it n to do that?

 

[jerryjerry05]

Re: '88 Force 85hp low top speed?



First ask yourself?? Can I change the plugs on my outboard? If you can, then you can do it?
You'll need a compression tester, then spark plug testers.
Then you'll need a couple things. A remote starter and a way to ground the plugs.
The red wires are the way to ground the plugs.
When you get the other stuff come back on and we'll give the directions.
Oh yea get a manual,factory if possible.

 

[SkiDad]

Re: '88 Force 85hp low top speed?

Nice clean boat! I'm looking at your pic and your prop looks pretty bad - that might be the reason for only 30 mph instead of 35, just a thought

 

[jerryjerry05]

Re: '88 Force 85hp low top speed?

Yea that props pretty rough.
Post a better pic?
If the one blade's bent as bad as it looks, your not getting the right results.

 

[pnwboat]

Re: '88 Force 85hp low top speed?

+1 on that prop. If you're looking to get some decent performance, get it fixed or replace it.

 

[88capri]

Re: '88 Force 85hp low top speed?

The prop is wrecked. The boat came with 2 that were in despicable shape, as is the skeg. I have a new prop and am will be getting a skeg guard. Tomorrow I'm going to GPS and test out my new prop (nothin fancy just an aluminium 13 1/4 X 17) but I'm hoping to see some over all improvement.

 

[88capri]

Re: '88 Force 85hp low top speed?

Nice clean boat! I'm looking at your pic and your prop looks pretty bad - that might be the reason for only 30 mph instead of 35, just a thought

Thanks, Ive been treatin her like a baby, first boat and all! Both the props she came with are tore down. The previous owner didn't take care of the boat, she's in good hands now though!

 

[88capri]

Re: '88 Force 85hp low top speed?

Hey all! Sorry I haven't updated. We hit the lake Fathers day and had a bit of a disaster, we started taking on water, FAST! I can post THAT debacle in another thread, screw holes through the HULL, look out for a ROOKIE mistake thread to come! So I had to take care of that, first.
Got it out this past weekend and got a GPS speed on her, she cruises at 28-29 mph, maxed 30 mph, gets to plane nicely. We had a BLAST!
That being said, cruising with the fam at just under 30 mph a good speed for us, we are happy with the performance my concern is whether or not the engine is performing as IT is supposed to under normal circumstances. I suspect it is, and without more testing it's hard to tell. Just looking for experience's from people with similar set-up's to let me know if my numbers are WAY OFF or with in spec?

 

[SkiDad]

Re: '88 Force 85hp low top speed?

my guess is your throttle is not opening up all the way - might just need to be adjusted some... or maybe you don't have a trim motor... if that is the case you may want to try one hole higher of the 4 holes. But then again if 30 is all the faster you need to go then so be it. Have fun - i grew up on a boat since i was an infant... just got my own boat in my 40's and it has been a blast to finally have my own to use whenever ! Kids have a great time too.

 

[Jiggz]

Re: '88 Force 85hp low top speed?

One good way to find out if the engine is performing up to par is to compare WOT RPM to max speed. If you have an RPM gauge and post your WOT RPM we can start from there.

 

[88capri]

Re: '88 Force 85hp low top speed?

I have a trim motor. I'll try adjusting the throttle. But like you said mitzsman we are happy with the performance so I'm not going to fuss too much!