225 Optimax Rough Idle, No fault light

[MarlinTini]

I have a 2000 225 Optimax that idles rough - think I dropped a cylinder. Just replaced the plugs - problem persists. Need to trouble shoot to find out if I have spark & fuel getting to the cylinder. Suggestions?? I plan to pull the new plugs out now that they have been installed and the engine was run for ~5 minutes to see if they were all firing. Any easy way to make a spark gap tester? Anyone know of a way to read the onboard computer w/o having to drag the boat and engines to a dealer?? Looking to learn more about maintaining these opti's. Any diagnostic suggestions would be appreciated. <br /><br />Thanks, Jeff.

 

[Reel Appeal]

Re: 225 Optimax Rough Idle, No fault light

Jeff,<br /> How was the motor running before you changed the plugs?Do the old plugs look all the same? A new sparkplug can be defective from the get-go.There is a easy test you can do.At night,remove the cowling and run the motor.Watch the back sparkplug area for flashes or external spark.There are inline spark plug testers available also.If the problem seems worse now than before the plug change,you may suspect a bad plug.Pull the plugs and compare each.If one looks vastly different or cleaner than others,there you go.If the plug is dry compared to others,fuel delivery problem.

 

[bret walters]

Re: 225 Optimax Rough Idle, No fault light

marlintini, where do i begin? the honest answer here is that there is not much you can do on your engine with out the dealer... but. a spark gap tester must be a sealed type tester, open gap will cause ecu problem and throw of your trouble shooting. perform a compression test first. next inspect your plugs, optimax plugs will be dryer than normal 2 strokes and close to black, heavy sooting is sign of cold running. if you find a suspect plug and compression is good, swap out suspect plug into know good cylinder, test run for short time and see if suspect plug looks any different. what spark plugs are in the engine?<br />if plug swapping test indicates problem is on one particular cyl. then look there for corroded wires,broken,grounded, connections for that cyl.<br />beyoond this i think you will needed to find a good service tech. with ddt. tester and training to get it right.<br /><br />florida is nice this time of year.

 

[MarlinTini]

Re: 225 Optimax Rough Idle, No fault light

Engine runs the same before and after plug change. No sparking apparent from bad wires. Pulled new plugs after running a few minutes. Btw, running the recommended optimax plugs. a couple of them were cleaner than the others. Kind of making me think it could be fuel delivery as in a problem with an injector on the #6 cyl. Anyone know where to get one of the ddt testers used by the dealers?? Not sure of the cost, may be too much $$ to consider.

 

[ODDD1]

Re: 225 Optimax Rough Idle, No fault light

Jeff, you are gonna drop some coin for a DDT....if I remember correctly, the DDT is over $700, the plug in cartridge you need is another $100, and you still gotta buy the cable that plugs into the motor........without it, a decent pressure guage set, the factory manuals and a working understanding of how all the different pieces on this motor play together, you wont get too far.... the old seat of the pants troubleshooting, swapping ignition coils,injectors works, but you need the DDT to do a cylinder drop.

 

[bret walters]

Re: 225 Optimax Rough Idle, No fault light

ok, here are the short cuts that may! help find the problem. it sound like this may be a failed direct injector. these are the injectors that are in the cyl. heads not the fuel rails. if you are mechaniclly inclined and will follow very carefully these instructions i can walk you thru. this. do not take any short cuts. <br />1. locate a factory service manual and read the theory of operation section in the ignition chapter, and in the fuel injection chapter. <br />2. remove the nuts holding the fuel injection rails on the heads.<br />3.disconnect the electrical harness' that go to the fuel injectors, and the direct injectors, and the cylinder head temp. sensors.<br />4.carefully pull the fuel rails away from the heads, do not remove any hoses or clamps that are stainless steel. the hoses are not long enough to get the rails off of the studs this is ok, place a small block of wood or a screw driver handle between head and fuel rail.<br />5.carefully remove each direct injector from head,<br />turn them and pull straight out of head, DO NOT PRY THEM OUT WITH A SREWDRIVER THEY CAN BREAK and are about 300.00 each.<br />6.look at each injector if the center is missing, you have a serious problem, find a good dealer.<br />7.if they all look ok they can be tested on the bench, sometimes they fail mechanically and do not open but electrically they are fine,this is why the ecu is not picking up a problem. to test them you will need a six volt lantern battery and two test leads with small insulated alligator clips ( radio shack ). DO NOT USE 12 VOLT BATTERY, ecu voltage out put to injectors is 5 volts dc. 12 volts will damage them.<br />8.hook test leads to battery. attach one test lead to one terminal in the inject. tap remaining terminal with the other test lead. you will hear a cliccking sound with every tap.if you watch close the center pintel in the injector will move also. it doesn't move much. .050 aprox.<br />9.test each injector this way if you find one that is not clicking this is your problem,replace is with a new injector-- the lastest version replacements are blue, only use blue.<br />10.if this does not find problem, find a dealer.<br />if you post an email adress i will email you directly. take your time this sounds complicated but it is not.