help with a 1989 force 125 wont go over 2000 rpms

[xstreamxxx]

i need help with this motor fresh rebuild just bought the boat at the end of june the guy i bought it from informed me of the issue of it not going over 2000 rpms but i have done alot of work on outbourds so felt i could fix it was i wrong i am at my wits end at this point what i found after getting the boat is cylinder #4 piston burnt .. drain back gasket broke flywheel magnet loose and soft after rebuilding power head and the other repairs i felt good that i found the problem got it all back together set timing sicked carbs runs great on the muffs so i take it to the river fire it up idle a little low so i turn it up let it warm up put it in gear set idle again and adjust carbs running great so i proceed out on the water get out of the no wake zone and go to open it up and it just bogs down so i back offf on the throttle re check a few things all looks good so i taxi around the water for awile at just over idle for the day get it home check the ignition and compression all seems good but found #2 coil had the ground wire broke in the insulation replaced it back to the river same results tested stator good tested all coils good seemed as if was still droping cylinder #2 so i got a cdi box for it changed that and put the muffs on it now all cylinders are firing good take to the water same result i have checke all wires and conections replaced plugs several times cleaned carbs rebuildt the power head nothing has changed please help

 

[Jiggz]

If you can post the compression numbers it will be great. Re-check sparks using the pull and listen method. While idling, pull each spark plug wire and listening for changes in engine tune. Try doing this quickly to verify no cylinder is missing and protecting the cd packs at the same time. Then do the "link and synch" which is posted on the sticky thread on top of this forum. Most critical you verify the throttles on each carb at WOT (control lever in full forward position) making sure they are at full horizontal, no more no less.

Install a clear fuel filter between the fuel pump and the carb fuel inlet. Do a test run on the water (bring with you a spray bottle with fuel oil mix in it, 1/3 to 1/2 full is all you need) and when motor will not go pass 2000 RPM at WOT, stop motor. Remove cowl cover and inspect the clear fuel filter.

If it is empty, then you have fuel delivery problem, i.e. leaky fuel hoses, faulty fuel pump, faulty check valves on primer bulb, restricted pick up tube or tank vent.

If it stays full, then you have carburetion problem, or electrical problem or even reed problem. Remove the carb's air covers, start engine again and ready for the next test. Make sure you are clear of traffic and distance from shore. Have a second person do the driving while you stay with the motor with your spray bottle. If at WOT and still bogging down, spray fuel mix directly into each carb. Just intermittent spray and watch for the motor reaction.

If rpm increases, there is fuel starvation problem on either of the cylinders fed by that specific carb
If rpm decreases, that carb is working properly
If no changes, those cylinders are either not firing due to faulty reeds, wrong throttle position, no spark or low compression.

Finally, make sure you are using the right spark plugs, BUHX or UL18V

 

[xstreamxxx]

comp is140 to 135 on all cylinders pulled plugs today thay all look to be fireing all have black film on them none seem to be washed like not fireing also pulled reeds out today and i can see light through a few of the pettals on cylinder #1 and #3 i will check with a clear fuel filter next weekend in the meen time i am just going to replace the fuel lines and primer bulb it probly needs to be done anyways,, another thing yesterday i was putting fuel in it and got 3.5 gallons in it and it blew fuel out of the filler neck not the vent .. but any way i asumed the tank was full got on the lake whent about 5 miles at just obove idle fished a little and went about another 5 miles and it ran out of fuel but when it was running out it seemed to start running better and felt like it was getting more power then about 30 seconds later it started missing then died out of fuel would it be to rich and would a vent restriction cause the fuel to spit out of the filler neck

 

[Jiggz]

With the fuel blowing out of the filler neck it tells me you likely have a clogged vent line which can be the cause of your fuel starvation issue. Investigate and try to blow back on the vent with the main filler cap open. Just make sure you do not use too much air pressure for safety. You just want to find out if it is clogged and if it is then you can clear it by disconnecting the line and blow air pressure into it (to prevent the crud or debris getting into the tank). If there is no restriction you should feel air coming out of the filler. With the clear fuel filter you can easily tell if the problem is with the vent since it will get emptied at WOT. You can also try using an external tank just to see if that will resolve you problems of not getting above 2000 RPM at WOT. As for the reeds, you can flip them over for now until you resolve your rpm problem.

 

[gregmsr]

Try running it with the cowl off...see if that helps any
Exhaust leaking into the cowl?
Happened to me once...