RPM drop while running at 3000-4000 RPM

[ray davis]

I have 1997 200hpSALTWATER SERIES YAMAHA OUTBOARD..ENGINE RUNS FINE OTHERWISE...CHANGED SPARKPLUGS..CLEANED IN LINE FUEL FILTERS..OIL SEEMS FINE...SQUEZZED PRIMER BULB WHILE ENGINE LOSING RPMS(NO CHANGE..STILL DROPS)...OPENED FUEL TANK COVER IN CASE VENTING WAS PROBLEM(TO NO AVAIL)...SPARKPLUGS ALL BLACK OILY...MAYBE ELECTRICAL PROBLEM....SEEMS LIKE SOME CYLINDERS MAYBE NOT FIRING AT HIGHER RPMS??????WHAT CAN CAUSE RPMS TODROP AT HIGHER RPMS????

 

[rodbolt]

Re: RPM drop while running at 3000-4000 RPM

hello <br /> I am going to assume this is an sx model that is EFI. chek the 02 senser. it should be cleaned once per year at least or every 100 hours. have you ever serviced the filter in the vapor seperator? have you ever serviced or just replaced the low pressuer fuel pumps? check the resistance of the spark plug caps.make sure the white plastic connector at the oil pump link rod is not broken dont be to concerned with High tech stuff untill all the low tech is tested.<br />need to post your maint schedule and approximate hours. if you still have the original pump impeller get rid of it now. the 97,98 impellers had a defect. they break apart and fail very suddenly<br />good luck and keep posting

 

[snookin]

Re: RPM drop while running at 3000-4000 RPM

Hi, had somewhat of the same, found out it was the GAUGES. after spending oh around 200 or so, a little prowing under the console, found lose wires and the other gauge was bad. A 2002 brand new boat. Hope this helps, good luck. Well back to fishing

 

[ray davis]

Re: RPM drop while running at 3000-4000 RPM

ship ahoy...engine not an EFI...have never serviced engine...just routine winterization..new plugs..lower unit oil...etc...i will put new impeller(water pump kit)before next season...have not touched fuel pumps...probably have 500 hrs on engine..no hour use gage...will check spark plug wires...maybe coil problem ....i think electrical problem of some kind...defective sensor of some sort..???oil sensor...i don't think a fuel problem...thanks for help...

 

[ray davis]

Re: RPM drop while running at 3000-4000 RPM

thanks snookin maybe

 

[ray davis]

Re: RPM drop while running at 3000-4000 RPM

thanks captain rodbolt....will test boot wires to sparkplugs...maybe coil or wires...start there...thanks ..will be in touch...going codfishing 11/8/03 at only 1/3 throttle but fish in my belly...hopefully!!!!

 

[rodbolt]

Re: RPM drop while running at 3000-4000 RPM

Hello<br /> please test the fuel pumps and carbs. if this is a non EFI engine you just described a fuel problem. Yamaha really does not have many electrical problems other than the cost on the rare occasion. if you continue to run it and its a fuel issue you may go from a carb job to a piston and carb job. caost of the carb job stayed the same<br />. outboard engines are not tolerant of poor running. they either run well at high speed of blow up soon.<br /> good luck and keep posting<br />but a fouled set of plugs will cause poor running as well. put in a new set and see

 

[ray davis]

Re: RPM drop while running at 3000-4000 RPM

Capt Rodbolt...thanks for info...bringing ship in for drydock..will use your advice...really appreciated....ray davis