2000 Johnson 225 won't go past 1500rpm follow up

[andyjwow]

Hi everyone, so this is a update from my first post. I have checked my compression,stator,timing and spark plugs. My shift switch interrupt is unplugged and still only getting 1500rpm max no matter if I'm 1/4 throttle or wot it stops at 1500 in the water in gear. https://forums.iboats.com/forum/eng...624699-2000-johnson-225-won-t-go-past-1500rpm is my first post. I haven't changed anything and I'm having more problems everyday. On the hose it started fine and idled fine didn't die this morning. About 2 hours of checking compression and checking carbs it started back firing and now dieing as soon as it drops from high idle to low. I unplugged the hose from fuel pump to carbs and it's a steady stream but not very forceful. I have 6 carbs and was manual giving gas and at around 1500 top right backfired/fired in carb. Noticed only a split second of my high idle jets spraying gas in 2 or 3 carbs then nothing then maybe another 2 shooting gas. Took fuel pump apart and looked very clean so maybe the electronics or not even fuel pump because I don't know. Won't idle now just dies and when manually giving gas backfires and tries to die at 1500 and some times I can baby it and get past 1500 and it works but I stop at 3k rpm.

 

[dingbat]

I would have to question why you’ve taken the shift switch out of the circuit.

Is the shift switch normally or closed?

 

[andyjwow]

I have the shift switch unplugged because I first noticed that I was only firing on 3 plugs in neutral. With it unplugged all 6 fire now. Am I missing something? I just see 1 ground and a yellow/blk wire that goes into a plug. I removed the ground and unplugged it to gain 6 plugs to fire to try and find out why I can't get above 1500rpm. I plan on adjusting it to fix it because you can wiggle it around and get it to show the correct numbers on a ohms. The weird part is that after I put the new lower unit on it worked fine for 2 trips as you can read from my link to the first post. I assumed with it unplugged it wouldn't cause anything to malfunction besides dropping rpm to shift. I can shift fine just can't get it past 1500 unless it puts it in a limp mode or safe mode that I'm not aware of no alarms go off.

 

[Chris1956]

If the motor detects overheat, it will limit RPM. Is the motor overheating?

 

[andyjwow]

Brand new water pump and stream of water is very fast. Some people back home have said fuel pump but is there a way for me self test it without taking to a shop.

 

[andyjwow]

Is there another way of checking if its getting hot? No alarm is going off and no leakage of water through engine. Best stream of water from a water pump i have seen also. People keep saying fuel pump like its starving but i would think i could get it o go above 1500rpm for even a split second then die but i cant.

 

[Chris1956]

Put your hand on the cylinder head. If she is too hot to keep it there for a few seconds, she is overheating.

Alternatively, overheat detectors could be faulty. You should have one on each head. Disconnect them and see if problem goes away.

Are you using premix gas/oil fuel? If so, pumping fuel primer bulb can assist fuel pump. If pumping fuel primer bulb fixes your issue, the fuel pump is bad.

 

[dingbat]

At this point, your best bet is to buy a factory manual for the motor.

In-depth step by step testing procedures for each component and system on the motor.

well worth the price of admission