2002 250 OX66 Shifts Hard

HeadHunt

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I had a thread a couple of months ago before I purchased this 23 foot Sailfish with the above engine. I am very satisfied so far but I want things in top condition since I will use the boat 30-40 miles out from the OBX. Everything is running OK but a couple of nagging complaints:<br /><br />1. When shifting into gear it kinda slams hard. I don't know how to describe it except it is not smooth. No grinding just a hard slam when it engages. Lower unit looks good, no water or metal. The engine had very regular maint. records when I bought it. Actually still under warranty.<br /><br />2. Very rough idle. I know this is a characteristic of these engines and it runs very smooth beyound 5-7 MPH but rough below that. Not much smoke.<br /><br />I get 40 MPH at 5300 RPM fully loaded. Wet weight is abought 5000-6000 lbs.<br /><br /> I plan to start running it hard out of Oregon Inlet, NC in about 8-10 weeks and just wanted to get some opinions. Any ideas??<br /><br />HH
 

rodbolt

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Re: 2002 250 OX66 Shifts Hard

if the idle speed is correct the shifting you describe is normal. its a mechanical clutch and is desined to slam hift. if you move the shifter slow and try to eae it into gear you will wipe out the clutch and gear assy. then ya get to se me or frank.<br /> on the shaky idle if all the maint and O2 sensor testing has been done and verified then yes I agree that the 3.1L yamaha is not really smoth idleing.<br />but look at the design of the shiftmechanism and it will be clear. its a mechanical slam shift not a smooth cone or disc type clutch.<br />did ya get the maint records ?
 

HeadHunt

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Re: 2002 250 OX66 Shifts Hard

Originally posted by rodbolt:<br /> did ya get the maint records ?
Thanks rodbolt. The engine has 220 hours. The maint. records show only spark plug and lower unit grease changes at 20 hrs. 50 hrs. and 150 hrs. The owner was kinda finatical about taking it in every 50 hours. However I do not think the dealer ever cleaned the O2 sensors or the VST filters. Since it runs good at high RPM I assume the fuel rail pressure is OK. I don't know if you would be interested but I would like to leave it with you one time after a trip to OI. I plan on fishing every two weeks beginning around the end of March. Do you think I am being overly cautious?<br /><br />Thanks,<br />HH
 

rodbolt

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Re: 2002 250 OX66 Shifts Hard

look carefully at the yamaha service intraval and you will note there is a butt load of maint you really need to catch up on.<br /> the intraval is calander OR hours WHICHEVER occurs FIRST.<br /> read heed and believe it.<br /> I see to many that get a 50 or 100 hour service year after year then fail cause the 200 and annual services were never performed. in fact last two dealers I worked at they would schedule just 100 hour services even though it needed a 200 hour service. <br /> were it mine and knowing a bad or clogged O2 sensor can and will cause a piston failure I would at least have it tested for proper operation.<br />the low pressure pumps on the 3.1L motors are very short lived and should be replaced at about 3 year or 400 hour intravals. a leaking low pressure fuel pump can wipe a rod or piston.<br /> ya need to find a tech that understands how the system works.<br />not a parts changer or a tech that is scared to spend your money.
 

HeadHunt

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Re: 2002 250 OX66 Shifts Hard

Well, there is a local guy who I hear is good but I do not know him. Maybe I will give him a call and see if he sounds knowledgeable about the O2 sensors, low pressure pumps and fuel pressure readings. One reason I asked about you is I of course spend alot of time there. Techs around here never see saltwater engines. Maybe after my conversation with the local guy I will drop you an e-mail. I have you in my address book.<br /><br />Thanks,<br />HH
 

rodbolt

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Re: 2002 250 OX66 Shifts Hard

ask anything you wish here or email me. be aware that I am rather low with email :) :) <br />but if you ask here someone else may get to read it as well.
 

HeadHunt

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Re: 2002 250 OX66 Shifts Hard

OK. I plan to purchase my own service manual. What maint. has this engine missed other than the O2 sensors, VST screen cleaning and replacing the low pressure pumps? I will then ask the local guy about the items that need to be done and see if I can get a feel about him understanding or just being a parts changer.<br /><br />Thank You<br />HH
 

rodbolt

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Re: 2002 250 OX66 Shifts Hard

tstat and water pump inspections,link and sync inspections there is a lot of maint for the 100 or 6 month and the 200hr or annual maint on that motor. object is to fix any issues before it breaks something else.
 

HeadHunt

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Re: 2002 250 OX66 Shifts Hard

rodbolt,<br /> I had a pretty good conversation with the local Yamaha tech my buddies recomended. He seemed to know his stuff. I asked him questions about the pressure on the fuel rails, low pressure pumps, link and sync and he seemed OK. I am taking it to him next Tuesday and he said we can pull the manual and look at all the recomended maint. from Yamaha and make a list. Right now I am thinking:<br /><br />Water Pump Replacement (impellor or the entire pump?)<br />Clean O2 sensors and VST Screen<br />Replace all low pressure pumps<br />Change lower grease<br />Change Plugs<br /><br />What about the thermostat? Should it be replaced? Are there any other items I should add to the list?<br /><br />Thanks Alot,<br />HH
 

rodbolt

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Re: 2002 250 OX66 Shifts Hard

if ya replace them every two years or so when doing the pressure control valve grommet and installing a water pump kit they never fail.<br /> look in the 03 to 05 marine technical guide and it will have the latest maint chart. testing the O2 sensor for proper operation after cleaning is imperative. it can only be done with the gearcase in the water to about its normal depth. the test procedure is in the marine tech guide, not sure if its in the manual. there are also some pencil zincs in the block and heads that need periodic inspection. the stbd side is a pain to access so no one ever does it.
 

HeadHunt

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Re: 2002 250 OX66 Shifts Hard

Originally posted by rodbolt:<br /> if ya replace them every two years or so when doing the pressure control valve grommet and installing a water pump kit they never fail.<br />
Are you referring to replacing the thermostat?<br /><br />HH
 

HeadHunt

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Re: 2002 250 OX66 Shifts Hard

Originally posted by rodbolt:<br /> testing the O2 sensor for proper operation after cleaning is imperative. it can only be done with the gearcase in the water to about its normal depth. the test procedure is in the marine tech guide, not sure if its in the manual.
Wow, how many shops actually do this? Can this test be done on the dyno?<br /><br />HH
 

rodbolt

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Re: 2002 250 OX66 Shifts Hard

yes the reference was to the tstats and no the O2 sensor cannot be tested on a dyno. it must have correct back pressure or the readings get all funny. in fact that motor is NOT reccomended to be run on a dyno nor test wheel. I have done it a few times but never to WOT.
 

HeadHunt

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Re: 2002 250 OX66 Shifts Hard

Originally posted by rodbolt:<br /> correct back pressure
That sounds like it must be tested while the boat is actually in a lake. How else would you get the proper back pressure?<br /><br />HH
 

rodbolt

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Re: 2002 250 OX66 Shifts Hard

either launch it or back it down the ramp. its the only way the test results have any meaning. anything else is just numbers.
 

HeadHunt

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Re: 2002 250 OX66 Shifts Hard

Originally posted by rodbolt:<br /> either launch it or back it down the ramp. its the only way the test results have any meaning. anything else is just numbers.
Well that isn't going to happen. This guy is an hour away from a lake as are alot of techs. Now I'm getting a little freaked. So, he is going to clean my O2 sensor and just re-install it, period. I guess that is what most techs do. What is a guy like me to do? Hope for the best?<br /><br />HH
 

rodbolt

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Re: 2002 250 OX66 Shifts Hard

that or buy the test harness and a digital VOM and check it yourself. takes 15 min or so and is simple.<br />but on the flusher it wont give correct and reliable readings, that you can deposit in the bank.
 

HeadHunt

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Re: 2002 250 OX66 Shifts Hard

OK, I am very appreciative of this advice. If I can ever, ever return the favor just let me know. You are always welcome in my boat or my treat at the 19th hole!!<br /><br />Now, I don't see myself becoming a technician anytime soon, with everything else going on in my life right now. So, I guess I will talk to this guy and get a feel for how he is going to test it. How about if we just replace the O2 sensor(s)? Same thing, must be checked? Surely guys that rig new engines do not wet them and test them.<br /><br />HH
 

HeadHunt

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Re: 2002 250 OX66 Shifts Hard

Well, I spent about 2 hours today reading technical info. on the O2 sensor. I found a nice article "Servicing Yamaha's Super Sniffer".<br /><br />Are these really about $280? <br /><br />At this point, I am just going to get a good, complete service, doing all the things we discussed and if the O2 sensor looks bad then I have a decision to make (have him clean it or replace it).<br /><br />If I do replace it, is it necessary to test it under load?<br /><br />Thanks,<br />HH
 

rodbolt

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Re: 2002 250 OX66 Shifts Hard

a test is still nessasary and to PROPERLY rig and deliver a yamaha it must be in the water anyway.<br /> a bad or incorrect O2 senor signal can wipe a piston. yes they cost close to 300 dollars and yes they go bad occasionally. the test harness is about 20 bucks and the VOM at radio shack is about 25 and the test procedure is in the 03 and 04 tech guides.<br />the output voltage should be .35 plus or minus about .1 volts and vary. to test the reaction remove the airbox. install the test harness,plug in your DVM and start the motor with the gearcase submerged. allow 5 to 10 min to warm up. now close off the upper air bypass hole in the top throttle plate. the meter should swing towards .9v. when you remove your finger it should hed back for about .2-.3V. then it should start scaling between .3 and .6 V at idle. if it does not its not working correctly and above 4000 RPM if it tells the ECU the fuel air ratio is rich the ECU will keep leaning the mix until a piston scuffs.
 
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