Rough idle in gear trimmed down

[New2me]

I dont know if its just age on the motor or what but the motor runs more rough trimmed all the way down verses about 1/4 trim upit idles smooth.Out of gear no change idles smooth.I cant recall it doing this in the past.

 

[New2me]

Re: Rough idle in gear trimmed down

I guess I need to add I have 1-1/2 cans of seafoam in 10 gal of prem fuel. I have ran it for 15min straight before giving it more throttle it doesnt get worse or better.

 

[MrBigbird]

Re: Rough idle in gear trimmed down

Check and make sure that your fuel line is not getting pinched off somewhere when the motor is trimmed. I had a similar problem and that is what the fix was.

 

[Mas]

Re: Rough idle in gear trimmed down

When the motor's orientation is different than perpendicular to the water, it also changes the orientation within the carb's float bowl. Depending on how your bowl float is hinged, one orientation could open the valve seat and flood the carb....thus idle rough!? When the motor is "trimmed all the way down" is it perpendicular to the water?

This is a total guess with no experience on this issue...but just a thought!

MAS

 

[rodbolt]

Re: Rough idle in gear trimmed down

mas may be closer than mas thinks.
when in the water two things change when trimmed full down vs up.
one is the amount of fuel in the bowl due to float orientation the other is exhaust back pressure.
if the compression is accptable on all 3 cylinders its time to go hunt the carb issue.
ditch the premium fuel, not only is it simply not nessasary but can and usually does cause a power loss at high speed.
MMI gives you enough information to be a danger to yourself and others.
its kinda like graduating navy boot camp and thinking your a sailor.
while attending a technical school shows a desire you must remember that school doesnt graduate techs just trainees.

 

[Mas]

Re: Rough idle in gear trimmed down

while attending a technical school shows a desire you must remember that school doesnt graduate techs just trainees.

I guess it's kinda like:

"What do they call the guy who graduates LAST in his class at medical school?"


Dr!


MAS

 

[rodbolt]

Re: Rough idle in gear trimmed down

even that Dr trainee still has to complete an internship and a residency.
that and a doctorate is a bit different than a 6 month couse covering 5 brands and none particularly well.
trust me I deal with MMI and other graduates year round.
some my actually make it as a tech oneday others simply wont.
we get probably 50 apps a year from people wanting to become a tech. we interviewed one friday that I actually like, he is also a recent MMI graduate.
I asked him to simply tell me how to remove the bearing carrier on a 10 yr old left hand case 3.1L yamaha.
man had never seen oxygen/acetelyne.
aint gonna happen without it and its not taught at MMI.
nor is burning out a bolt or drilling and heli-coiling.
however by the simple fact he went for formal training and graduated tells me he is ambitious and willing to put in training time.
couple that with this guy spent 3yrs in the USCG and he has a shot.
gotta see his DD 214 first, if the 214 is clear my vote will be to hire the man.
so like I say, being a tech school graduate normally gives you a base to build on but only a base and just enough information to be dangerous .
btw, I graduated top in my class in BE/E,FC(A) and FC(C) school and hit the fleet as a CIWS tech. took a few years and some circuit cards to actually BE a tech. but everyday I learn something, like what code 9 means on a carbed 3.1L yamaha.

 

[Mas]

Re: Rough idle in gear trimmed down

btw, I graduated top in my class in BE/E,FC(A) and FC(C) school and hit the fleet as a CIWS tech. took a few years and some circuit cards to actually BE a tech. but everyday I learn something, like what code 9 means on a carbed 3.1L yamaha.

OK Mr. Rodbolt, you just blew me away!

MAS

 

[New2me]

Re: Rough idle in gear trimmed down

I like your attitude Rodbolt.You are correct about the school its a starting point,An entry level training course, I by no means claim to know all or can do all because of MMI.Lets face it there is no replacement for field experance.I chose to go back into the oilfield after completing the school.Thanks for the advise it am planning on checking compresion as soon as I can get back to the beach,Currently in the gulf of mexico on a rig.I have been chasing down the idle for a few weeks.Thanks agian all.

 

[New2me]

Re: Rough idle in gear trimmed down

I will edit my MMI sig ,I am trying to state that even with informal training I still can answer even some basic questions.O and they did cover drilling and heli-coiling but thats it.

 

[JustJason]

Re: Rough idle in gear trimmed down

I finnished MMI years ago. I hated it. I would complain because people were cheating on their tests and the instructors just didn't care.
I remember the volvo test we took. 50 questions, multiple guess, open book. Every dam question was about what is the "spec" for "xyz" on an "AQ???" blah blah engine. You Had to look them all up. It took me 2 1/2 hours and I missed a Q and ended up with a 98.
Without being racist, just realistic, 4 white guys and 3 cubans who hardly speak english, who all sat at the same table, passed in their tests in 1/2 an hour and they all got 100's. Stuff like that happened all the time, drove me crazy. It devaules my degree to nothing more than a POS.

 

[rodbolt]

Re: Rough idle in gear trimmed down

hey, I apologize for the MMI thread.
the mods have already busted my chops and I apologized for any offense and still will.
wasnt trying to knock anyone or any particular school.
most posters here wont belive how many PM's I get from persons in community colleges or tech schools that I actually call on my nickle.
as a human being I am mostly worthless, as an outboard/sterndrive tech they say I am ok.
so I am sorry if I offenended anyone but its just how I am.
its a wonder the wife actually married me last november.
the only reason, i think, why I post here is because somehow somewhere I ended up with alot of knowledge and failing health.
so I try to pass on the latter and ingnore the first.
I figgue would be a shame to die with all this stuff in my head and not try to pass it on.
but I am still human and I can be acebric even for those that have met me at the Blue Crab.
in the mean time, fair winds and following seas.

 

[New2me]

Re: Rough idle in gear trimmed down

No need,I do kind of understand were you are coming from,I graduated about 9 years ago from there and Just J,you are right also.I am the type that take my life,work,toys seriously,and pride my self that I did do something with all my abilty not half ***,There were alot maybe 1/2 the class that were treating it like it was High school or something.I was I guess the rare one that took down every note,and learned what I could to get my moneys worth.
Ow back to my issue I was told to use a spark board when checking compression as it may mess up the CDI box,is there truth to that or will I be fine hanging the wires off and cranking it.

 

[JustJason]

Re: Rough idle in gear trimmed down

Ow back to my issue I was told to use a spark board when checking compression as it may mess up the CDI box,is there truth to that or will I be fine hanging the wires off and cranking it.

If your cranking it with the key off using a seperate remote starter button then the ignition system will be off, It won't matter if you use a spark board or not. On a seperate note though, you should check for spark with a spark board. The yamaha's ignition systems don't run as hot as other manufactor's... But you should still have good spark across a 7/16's gap. With the yamaha's it's not quite as blue.

 

[rodbolt]

Re: Rough idle in gear trimmed down

actually Yamaha ign system run as hot or hotter than the rest given the same year ranges.
if you dont believe it spring for the 250 dollar snap-on Kv tester and have a look.
most single electrode plugs gapped in the .035 to .045" range you will see about 7-10 KV. most engines with surface gap,twin electrode or gaps over .060" you will see 10-15 KV.
if the plug becomes open you most likly will see over 20KV if fouled then something less than 2Kv same as a blown piston.
I usually combine my spark test with my compression test just cause its simple.
but either disable the ign system or use the spark tester.
with no electrical load on the secondary side then secondary voltages can spike to the 35-45 KV range and can arc through coils. the CDI still sees something in the range of 100-150 V from the charge coils.
that and ,especially EFI, if you dont disable the ign/fuel systems and fail to control the spark you may get to see a fireball .
never did it but I watched it be done on a 200 EFI mariner.
luckily I had enough time to alert the forklift driver so he got to watch it too.
what made it so funny is I told the backyardigans what not to do like 5 minutes before.

 

[New2me]

Re: Rough idle in gear trimmed down

I used an old compression tester and it was 125psi across the 3 cyl I think the guage is off a bit but what should it be.

 

[patrick4266]

Re: Rough idle in gear trimmed down

Rodbolt you sound a lot like me except were in different fields. I was a welding instructor for 35 years seen it all done it all ect. Most people who can run a bead call their selfs welders and it is problay so with all mechanics and applys to other fields as well. Myself i do no care if your a worthless human being or not. i am just glad to have some with your knowledge, who is willing to help us out, in here.

 

[rodbolt]

Re: Rough idle in gear trimmed down

new2me
leave that tag line mostly alone, ditch the clueless part.
at age 18 I had a full scholarship to Denver Automotive Instsitute.
however I fell in love, got married and turned it down.
so I am aware of what it takes and costs to go to school and do something.
just remember doesnt matter what field your in or what ranking in the class you were it all comes down to 2 things.
1 is can you rapidly modify what you were taught to accept changing technology?
and 2 is can you teach yourself a better way with every job?.
do that and in 5-8 years you may be a tech
your compression tester is old, so are mine, both mine are faily cheap models as I wont pay snap on prices.
however we dont look for actual numbers. thats NASA stuff.
we look for is any cylinder different with the same test and the same environment.
tak the average V6 two stroke.
what you have is 6 tiny motors attached to the same crank.
all have to be close in every way.
so keep the tag line, ditch the clueless and go learn, be better than the rest but always remember the basics.