Loss of speed/power

stephenspook · Post by **stephenspook** » July 21st, 2003, 11:41 am

Hope someone can help me out here. Last weekend I took the 19'CC w/120 HP Force out. Was going max 30- mph when all of a sudden I lost power and could only do less than 10 mph. After 45 minutes of limping like this I regained some speed but only to 20 mph (my max is usually 30). Took it to the mechanic, he checked compression, changed plugs, changed fuel filter. Said it looked fine. Took the boat out this weekend and still can only get 20 mph out of it. Any ideas? Thanks for any help you can give me.

Post by **wevans** » July 21st, 2003, 1:07 pm

What year is the motor and what are the RPM's at full throttle, does it have a water seperator?

dowawoo · Post by **dowawoo** » July 21st, 2003, 6:17 pm

Well went through something similar last year, only 90hp evenrude, checked the compression and all checked out, problem, well ended up rebuilding, one piston, number one cylinder, ring broke, would only show up a problem when under power, on a hose sounded good, idle good, no power under a load...I found out by pulling the heads and looking in the cylinder....
Two cycle engines depend on suction from the piston to pump fuel to the cylinders...just a guess
Don

dowawoo · Post by **dowawoo** » July 21st, 2003, 6:19 pm

Hey, did you check the prop, could it have spun?
Don

gatorsuf1 · Post by **gatorsuf1** » July 21st, 2003, 8:57 pm

How can I tell if the prop is spun? Not sure what that means...

gatorsuf1 · Post by **gatorsuf1** » July 21st, 2003, 8:59 pm

It is a 1999, does not have a water separator. I believe my rpm is usually 4500 to 5000. I can't say I remember what they were since this problem, I'm guessing less.

gatorsuf1 · Post by **gatorsuf1** » July 21st, 2003, 9:00 pm

Dowawoo, the powerhead is a rebuilt, just had it done a few months ago.

Post by **wevans** » July 22nd, 2003, 9:16 am

The prop has a rubber center that is bonded to actual prop, if this bond is broken, then the prop can spin on the center, thus a spun prop. To check it, put the motor in gear and then try to turn the prop by hand, if you can move the prop without the shaft turning, it is spun and needs to be rehubbed. If your RPM's are still in the 4500 to 5000 range the prop needs to be inspected further. Does it sound like it is running on all cylinders?

stephenspook · Post by **stephenspook** » July 22nd, 2003, 12:15 pm

Thanks wevans, I'll try your suggestion. It does sound like it is running on cyclinders.

dowawoo · Post by **dowawoo** » July 22nd, 2003, 9:46 pm

One more ideal, is it running hot? Rebuilt powerhead, how many hours do you have on it?
If it were mine, I would look at the simple stuff, are all the wiring hooked up right, plugs firing, coils not cracked, crossed, fuel good, not old, if mixed, is it the correct mixture....
If all that is correct and your prop isn't spun, take it back to who rebuilt it and take that person for a ride...
Wish I could be more help, know from my own dealings how that can frustrate you...good luck
Don

Post by **Sea Fox** » July 22nd, 2003, 10:06 pm

Stephenspook, I have a freind who had almost the same problem and he had to replace the power pak. I have also seen old gas give the same problem. Good luck

Post by **jonguthrie** » July 24th, 2003, 5:40 pm

One other thing to look at, that motor is known for having coil problems. While the motor is running check the spark on each cylendar. Look for a spark that is weeker and different color on one cylender.

Post by **tin can** » July 24th, 2003, 9:56 pm

I'm not trying to be a smartazz, but it could be a hundred different things. Take it to Pete, at Sunshine boats. He knows about Force outboards.

Post by **wevans** » July 25th, 2003, 7:24 am

Now TC, we all know that you don't have ta try

dstockwell · Post by **dstockwell** » July 25th, 2003, 7:28 am

Nope, he has that down purty good.

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