badly running evinrude 40hp vro

[antsduc]

anyone help my 40hp starts up runs lovely at tick over and as you engage the gear but as the revs pick up the engine runs high then low then high then low and then when you pull the throttle back slowly it will tick over lovely again .i have cleaned the carbs set the floats but still the same thing .

 

[imported_lorin]

Re: badly running evinrude 40hp vro

This may be a long shot-but I once saw a 40hp that showed the same behavior-the rpm's would change quickly and extremely between high and low. The problem turned out to be the inner ring of magnets on the flywheel which encircle the end of the crankshaft had become loose. These magnets control the triggering of the ignition, so as they moved back and forth the timing would advance and retard continuously, increasing and decreasing the rpms. You can look for this problem by using a timing light and see if the timing is jumping around as the rpm's change. If so, remove flywheel, grab ring of magnets and twist-see if they move. If the rpm change is not erally very extreme then it might just be an air intake leak behind the carbs somewhere.

 

[jtexas]

Re: badly running evinrude 40hp vro

also examine your wiring, stator to powerpack to coils, look for loose connectors, burned, missing, chafing insulation, corrosion, especially where components are grounded to the engine block.

I feel kinda silly asking this, but please define "tick over" for me. Thanks.

 

[rickdb1boat]

Re: badly running evinrude 40hp vro

Try pumping the fuel primer bulb when this happens and see if it smooths out..Assume you mean it runs good at idle??

 

[tashasdaddy]

Re: badly running evinrude 40hp vro

you could need a linc and sinc. this sets the carbs and electrical together so they perform properly. also it could be loosing spark, take a timing light with you, connect it and when it starts acting up check for constant flash on the timing light, try it on all plug leads.

 

[antsduc]

Re: badly running evinrude 40hp vro

also examine your wiring, stator to powerpack to coils, look for loose connectors, burned, missing, chafing insulation, corrosion, especially where components are grounded to the engine block.

I feel kinda silly asking this, but please define "tick over" for me. Thanks.

 

[antsduc]

Re: badly running evinrude 40hp vro

HI MATE THANKS FOR THE REPLY WHAT I MEAN WHEN I SAY TICKOVER IS WHEN ITS STARTS IT RUNS FINE, SOUNDS NICE NO MISSING I CAN PUT IT INTO GEAR AND IT STILL RUNS FINE UNTIL ABOUT QUARTER THROTTLE THEN THE RVS GET HIGH THEN LOW ,HIGH THEN LOW BUT AS SOON AS YOU PULL THE THROTTLE BACK PAST QUARTER IT RUNS FINE HOPE THIS IS OF HELP CHEERS TONY.

 

[tashasdaddy]

Re: badly running evinrude 40hp vro

possibly clogged high speed jets in the carb. or faulty fuel pump.

 

[jtexas]

Re: badly running evinrude 40hp vro

is it a sudden RPM change, like flipping a switch, or more gradual? sudden change points to electrical, otherwise fuel restriction.

If pumping the primer bulb helps it recover, prime suspect = fuel pump.

You don't say what year (model # might help), but if it's a push-to-prime system (vs. choke plates), try activating the primer while its bogging...if it surges rather than bogs worse, indicates carb rebuild is in order.

[just as an aside...all caps is less readable...it's considered the on-line equivalent of shouting]

 

[antsduc]

Re: badly running evinrude 40hp vro

is it a sudden RPM change, like flipping a switch, or more gradual? sudden change points to electrical, otherwise fuel restriction.

If pumping the primer bulb helps it recover, prime suspect = fuel pump.

You don't say what year (model # might help), but if it's a push-to-prime system (vs. choke plates), try activating the primer while its bogging...if it surges rather than bogs worse, indicates carb rebuild is in order.

[just as an aside...all caps is less readable...it's considered the on-line equivalent of shouting]

 

[antsduc]

Re: badly running evinrude 40hp vro

its a 40hp vro model but the oil injection has been removed its probably early 90s model its not the push to prime its lift the lever to choke ,activating the primer makes no difference .

 

[tashasdaddy]

Re: badly running evinrude 40hp vro

lifting the lever doesn't choke it, it only sets the idle speed higher. check your primer solenoid and see if it's working which way is the little red lever on the prijmer turned, it could be in the manual mode and flooding the engine.

 

[rickdb1boat]

Re: badly running evinrude 40hp vro

Might be the timer base sticking. Have someone slowly move the throttle lever forward(Not running) and observe the timer base under the flywheel and see if it moves smoothly.

 

[antsduc]

Re: badly running evinrude 40hp vro

lifting the lever doesn't choke it, it only sets the idle speed higher. check your primer solenoid and see if it's working which way is the little red lever on the prijmer turned, it could be in the manual mode and flooding the engine.

 

[antsduc]

Re: badly running evinrude 40hp vro

the little red lever is pointing towards the carbs how can i check that this is working properly .before it started playing up it ran great then it would bog down just after half throttle and now it does this .