1988 johnson 225 does not go above 3000 rpms

[85merc200]

1988 johnson 225hp carb<br /><br />alarms system never worked since i got the motor<br />90 psi check days ago<br />new plugs<br />new fuel and all filters<br />rectifier was replaced<br />all magnets are good<br />thermostats replaced<br />water pisses strong<br />all carbs were mechanic rebuilt and has been running fine for over a month now.<br /><br />problem seem electrical, any help please<br /><br />problem started with a surging problem running along fine then it started to go up in rpms then down up then down all by it self, now on the hose i can hear it skip a beat and on the water could not get above 1500rpms....<br /><br />any ideas, thanks i hope i gave all info, if i miss anything please ask

 

[R.Johnson]

Re: 1988 johnson 225 does not go above 3000 rpms

This is a problem where you have to start from go! compression, ignition, fuel. You will need a service manual, and proper instrument's, plus tool's to solve a problem like this. A fix on this engine can get very expensive if you start throwing part's at it. You may well be better off with a dealer.

 

[85merc200]

Re: 1988 johnson 225 does not go above 3000 rpms

i havent put a dime into it since the problem i listed what was previously done so as to "rule" it out....<br /><br />could the problem be a power pack ? or coils,<br />i'm also thinking i should fix the alarm system, this motor does have one right ?

 

[DHPMARINE]

Re: 1988 johnson 225 does not go above 3000 rpms

85merc200, First answer is very good advice,but one thing to try to narrow things down.What happens if you pump up the primer bulb when motor is acting up?<br /> You may have a weak fuel (VRO) pump.<br />DHP

 

[85merc200]

Re: 1988 johnson 225 does not go above 3000 rpms

sorry no vro, it looked like it was replaced with a newer fuel pump only (vro disconnected)<br /><br />i'll try the primer bulb pump up and see if it goes

 

[BrianTindall]

Re: 1988 johnson 225 does not go above 3000 rpms

Could it be going into S.L.O.W. mode?

 

[rickdb1boat]

Re: 1988 johnson 225 does not go above 3000 rpms

Try disconnecting the temp sensor(s) and see if it helps. Sometimes a faulty temp sensor will keep it in the slow mode. Sounds like it's in the S.L.O.W. mode to me. Pack may be bad, but try the basics first...

 

[85merc200]

Re: 1988 johnson 225 does not go above 3000 rpms

how do i disconnect the temp sensor ? sorry i cant afford a manual just yet...thanks

 

[clanton]

Re: 1988 johnson 225 does not go above 3000 rpms

You said VRO replaced, with what? A single old style fuel pump only, will not pump enough fuel for this engine.

 

[85merc200]

Re: 1988 johnson 225 does not go above 3000 rpms

yes its a single fuel pump, it looks new (shiny) came with the engine like that, i assume previous owner ditched the vro and replaced with NEWER fuel pump only.....boat did run great everyweekend before this problem and it can hit 5800rpms easily before...<br /><br />you know what could the fuel pump gotten dirty and gunk up ?, i was having dirty fuel problems<br />but i do have a water/fuel seperator and an inline filter before the pump...<br /><br />motor does skip a beat (coughs)at idle, and it seem to idle a little higher now, before it was perfect.

 

[85merc200]

Re: 1988 johnson 225 does not go above 3000 rpms

things i will check tommrow after work<br /><br />1. pump the primer bulb and see if it acceletates<br /><br />2. look for a "tan color" wire which from my research here is the temp sensor and disconnect it.<br /><br />3. look for strong spark from all 6<br /><br />will post results tommrow

 

[clanton]

Re: 1988 johnson 225 does not go above 3000 rpms

If it is a single Evinrude/Johnson pump, when you get the engine running well, it is possibe that the engine will run lean and burn a piston.

 

[85merc200]

Re: 1988 johnson 225 does not go above 3000 rpms

clanton, what should i do about this "weak" pump,<br /><br />replace it with ?

 

[85merc200]

Re: 1988 johnson 225 does not go above 3000 rpms

ok bear with me hear guys...<br /><br />this weekend i was out in the water curising at 4000rpms (approx) then this surging thing happen,<br />idle back with the trottle all the way down all i got was 1500rpms, got to the dock<br /><br />put the engine on the hose, looked at it ran like crap,,,later that day i changed the inline fuel filter (which was very very very dirty), started motor and reved it up LIFTING UP ON THE THE LEVER (NOT IN GEAR) well motor ran to about 2000rpms and no more....so naturally i thought the problem still exist...<br /><br />today i went check the warning horn it by grounding the tan wire with the key switch on,,,nothing did not hear anything started fine and i pumped up the blub to see if the minor sputter would go away while engine running,,,nothing, I then hit the key switch engine died, indicating fuel was being added,good...I then put the motor in gear and with prop clear i throttle up guess what it accelerates fine took it to 3400 brifly...great<br /><br />so it looks like the fuel filter was the problem and also it did NOT have any clamps where the hose attaches to the pump. The LIFT UP LEVER does not make the motor rev very high (normal)...All is good except the my overheat warning horn does not work at all. i need help in fixing that, and i will do a few searches as well....<br /><br />thanks to all that helped.