Is this what I should expect

I took out my new (used) 16ft, 1985 Ebko open bow with 85 hp Force outboard today. Listed below are the conditions and performance. Please let me know if this is what I should expect.

Boat: 1985 Ebko open bow
Motor: 85 hp Force outboard
Load: Full tank (about 14 gal.), three adults, balanced load to keep boat level.
Weather: Sunny, 10 mph wind, lake swell 6-12 inches max.
WOT: 4000 rpm on onboard tach.
Max speed: 31mph on both speedo and gps.
Prop: 17 " pitch. Prop is a bit nicked but not bad.

Is this what I should expect from this set up and scenario? I was hoping for mid thirties at least on the speed. The motor sounds strong; no missing or lagging. I trimmed it pretty well, maybe I could have done better on the trim but not by much. Any opinions welcome.

Thanks.

Re: Is this what I should expect

You need to check your tachometer, that motor should be over 5000 rpm at WOT. My 16" Tuffy Walleye boat with 90HP Merc does close to 50mph and I run a 22 pitch Laser II prop.

Re: Is this what I should expect

I agree motor needs more rpm to run right.

Re: Is this what I should expect

I was thinking that the motor has more left in it myself. It certainly didn't sound like it was maxed out or close to it. I suppose I need to look at throttle adjustments?

Note: It seems like I have to push the throttle lever almost have way forward for the rpm to increase. Old or slack cable? Adjustment on the motor maybe?

Re: Is this what I should expect

The 85 force was never a strong engine compared to OMC and Merc and three adults in a 16 footer is a decent load. However: Your RPM should be up around 5500 for best performance. and I would expect about mid 30s top speed.

Do a compression check to be certain the block is in sound mechanical condition. Check the carb linkage to be certain that all three are opening fully and equally.

Check the fuel lines and change the fuel pump diaphragm so it is getting the full delivery of fuel it needs.

Double check spark to be sure all three cylinders are firing.

Finally, if the prop is 19 pitch, try a 17 pitch prop. If you can find the lower unit off a 90, it is 2 to 1 gearing and will perk-up the engine considerably. You can also try raising the engine one hole--one inch BUT there is a danger that it will start ventilating at that height.


ABOVE ALL: DO NOT MESS WITH THE IDLE NEEDLES! Setting the carbs too lean WILL result in melted pistons.

Re: Is this what I should expect

I'm a pretty good car mechanic. After thinking about it and talking to my wife, who was with me, I'm thinking it's along the lines of the throttle cable worn, stretch, or something similar to that. Like I said, the motor sounds strong, it's just not being maxed out. Are there adjustments at the throttle lever itself I can make (like taking up any slack). I'm going to order an manual for the motor. Are the Seloc manuals good?

Re: Is this what I should expect

Cable adjustments are made at the engine. Remove the air box. Move the throttle lever full open and then check the position of the throttle blades in each carb. They should be perfectly parallel to the carb throat. Adjust accordingly. There is also a link & sync procedure that synchronizes ignition timing with throttle opening. That procedure is covered in the service manual and is far too detailed to cover here. Just don't start in the middle. It must be started at the beginning and carried through step by step to completion.

Re: Is this what I should expect

Silvertip.....

Wise words. I will order the engine manual and do adjustments in the right order. I won't be taking the boat out again for several weeks so I have time. Still learning the two stroke engine game.

Re: Is this what I should expect

Throttle cables will not wear or stretch and no adjustment should be necessary to them because the throttle STOP is on the timing tower inside the engine hood. The control handle will move as far as the stop lets it go. The ball end link between the tower and throttle cam is where you adjust carb butterflys for full opening. The aluminum bar on the side connects all three carbs and if the screws have loosened, the top two carbs will not open as far as the bottom one.
Force uses a "goofy" throttle cable arrangement. The sheath is the moving part and actuates the linkage. The piano wire core is stationary. Because of this, it is necessary to have a loop of cable in the splashwell for proper operation. Cables that are too short or bent to too small a radius will bind.

Throttle and shift cables CAN rust and break though.

If you go over to the Force/Chrysler forum and search my posts, you will find a lengthy one on adjusting carbs and synchronizing timing and carb opening.

Re: Is this what I should expect

Non verified specs for WOT rpm and gear ratio for an 88-85HP Force.

http://www.piranha.com/motor_specs.php?id=3103