125 force rpms maxing out

[19732009]

can anyone help i have a a 1988 bayliner cobra 18 with a force 125. when I'm going wot 4100 rpm and only at 32mph for about 5 mints and than the rpms will jump up to 6000 or max and the speed will not change. the motor does not seem to rev up more when the rpms max out. at first i thought the prop was cavatating so i got a fin did not help. could the rpm gauge not be working right. i just changed the fuel pum and all new fule lines. i have a 13x17 prop pleas help.

 

[pnwboat]

Re: 125 force rpms maxing out

If you have one of those square US Marine tachometers that has a display that looks like a graph, I would suspect it may be bad. If the tach is jumping up to 6000 RPM's and you don't notice any audible difference in the engine speed, It's probably a bad tach. I had a similar set up. I had to constantly tap on the tach to get it to read correctly. I finally replaced it.

 

[jerryjerry05]

Re: 125 force rpms maxing out

If all you can get is 4100RPM then something is wrong you should be able to hit 5400RPM and close to 45MPH.Do a compression test.Then a spark test.

The tach will jump for no reason.There is no fix other than to tap on it.Maybe spray some WD on the contacts.
Get rid of the fin it will actuall slow you down.J

 

[19732009]

Re: 125 force rpms maxing out

the only resown i got a fin is because my motor is about 3 inch's to high

 

[19732009]

Re: 125 force rpms maxing out

i do have a in line tank could it be getting a lot of moister

 

[jerryjerry05]

Re: 125 force rpms maxing out

Do a compression test and then a spark test.Post your results.J