New to me 2008 Venture not running right!!

[Flash105]

I've changed the plugs, flushed the tank with fresh fuel and SeaFoam, still not running correctly. 1st through 4th is OK, then when I go into 5th it runs like it's starving for fuel!! 65mph is top speed! Where should I start??? I've read where it could be a blockage behind the fuel mixture screw, where would I locate the mixture screw to try to flush out the blockage?? Thanks for all the help!!

[cecdoo]

I would make sure the tank vent is clear by inserting a copper wire or the like in there, then blow air thru vent hose to be sure its clear. Then check fuel pump is working properly, they are known to act up. At what speed are you going into 5th gear, these motors like to rev, it wont pull if you are dropping it into 5th at 35mph. You ought to be going into 5th at 65mph. When you say it runs fine in 1st thru 4th, can you hit rev limiter in each gear? If so you are going way faster the 65. I am sure you will get lots of other ideas, I always start with the easy stuff first. Oh and welcome to the family.

 

Good Luck, Craig

[Patch]

I've changed the plugs, flushed the tank with fresh fuel and SeaFoam, still not running correctly. 1st through 4th is OK, then when I go into 5th it runs like it's starving for fuel!! 65mph is top speed! Where should I start??? I've read where it could be a blockage behind the fuel mixture screw, where would I locate the mixture screw to try to flush out the blockage?? Thanks for all the help!!

 

Perfect timing! The other day I dropped my marbles (actually my brother cut the seam and they just fell out!)

 

So lets deal with 5th gear: if you are shifting correctly then you power on in one gear down regardles of which ever gear you are cruising.

5th is an overdrive or final gear, if you go past 5th then of course you will find the elusive reverse gear!

Here's the important piece of information: Yamaha did not miscalculate the 5th gear ratio; it is set for lite acceleration but primarily for distance/range which translates to miles per gallon or H.W. tank rang!

When you are running all 4 Jugs within there specified bench marks then the contribution per cylinder will provide the torque thru the crank output - to leverage the 5th gear!

That assumes the bike/mass is traveling at the correct speed for 5th, above 55 MPH.

If on the other hand one or more cylinders is not contributing enough to crank torque THEN you will see its effects as the 5th gear ratio reverses effort or becomes dominant!

 

That is how it works to dispel the myths resounding 5th.

 

"then when I go into 5th it runs like it's starving for fuel!! 65mph is top speed! "

 

this has nothing to do with fuel pilot/mixing screws!

 

BUT it may have to do with throttle position sensor? It is possible the unit has a flat spot.

 

If the bike is running out of fuel then the bike should kick a bit in high gear!

 

I tired to keep it as simple as possible it is what it is, Carl!

 

Let us know if you need more help Flash.

cedoo post is on the right track but if as he mentions you can sustain rpm in 4 the then likely the problem lies above as mentioned!

Edited May 17, 2020 by Patch

[Patch]

While reading the forum I found another thread of yours where you mention misfiring.

This answer would help us better understand what is the problem at 65.

Take it to 4th, and ride it to the 65 MPH, hold it there in 4th a couple of minutes, how does it behave?

Next see if she will go past that 65 to whatever you feel most comfortable at, for a couple minutes then note that.

At both marks note the position roughly as it pertains to throttle twist. Do you know how to do that? 2 pieces of tape, one fallows the grip, the other is stationary on the grip mount. Make one mark throttle at rest, the second one, throttle wide open, find the middle make a 3rd mark, and that is all you need to do!

Then report back with the throttle position you noted (approx) at which speed you develop the issue and in which rear... (we are looking for 4th gear results)

 

That will at least inform us at what angle the throttle plate is and which circuit may be the issue?

It could also direct us away from the carbs?

[Flash105]

Thanks for the suggestions!! I actually had to ride the bike today around 70 miles to get it to the shop. I poured another 1/2 can of seafoam in the tank and before I got to the shop, it was runnign some better. They are doing some other things to it and are going to check the electrical and fuel systems while there! The shop I am using is behind a month, some others were 2-3 months behind.. Will not be getting it back anytime soon but let you know when I know. I really like this bike and am looking forward to many future ride. Thanks

[Marcarl]

If the dealer is going to be month before they get to your bike,, I would be getting it back, if it's running as good as you say. One month + of not riding could translate into 2 weeks of riding and 2 weeks of learning how to do it yourself, with the help you can get here. We respond quickly, sometimes immediately, and if you are really stuck you can always call somebody to get you through the mess you might think you are in.

As Patch said, the mixture screws have very little to do with how the bike runs down the road, once the RPMs are above 1500 they are pretty much out of the picture, so not to worry about them unless you have an idling issue,, which you did not mention.

If you changed all the plugs and gabbed them right, and didn't end up resetting them in the process of insertion, then we can assume that they are working as they should. You need 3 things to make an engine perform, 1 is spark, 2 is fuel, and 3 is compression. That is very basic. Assuming you have spark on all cylinders, the next issue would be fuel, and as @ceedo mentioned do the easy stuff first to make sure fuel delivery is available. If that proves out to be fine, then go the next step and that would be carbs, and you did say that it seemed to run better after your trip,,, that's a good indicator, but I don't have a lot of faith in SeaFoam, it's real good as a maintainer, but not much good as a fixer. Use a quality carb cleaner in the tank and don't be cheap. Being cheap will only add to the cost.

If you do get it back, then do as Patch suggested on the way home. Actually, add some good cleaner to the tank before you leave and stay out of 5th gear just to get some fuel through the carbs and also to get the reading he is looking to analyze.

Keep us posted as to how you make out,,, we are interested and it doesn't cost you anything,,other than friendship.

[Patch]

For what its worth maybe future members reading thru and from here anyways, emulsion tubes gummed up

Sea Foam is a passive product when it comes to carbs, works very well tho in the crankcase.

Edited May 17, 2020 by Patch

[Flash105]

It's in the shop for new tires, getting to check the rest while it is there! Thanks

[steamer]

I am almost positive one of the carbs has a plugged high speed jet, the fact that the sea foam showed some improvement indicates this. For those that don't believe in sea foams powers, I can tell you first hand while working at john deere dealer and seeing time after time just how well this stuff works. so the next time you take your mower or rider in for a carb clean and pay $85, they probably put some SF in a fresh tank of gas and let it run for a couple of hours. Our shop made a killing the first year the Gov made unleaded gas mandatory.

 

 

.

[Patch]

Our shop made a killing the first year the Gov made unleaded gas mandatory.

 

.

 

Most of us agree it is a good maintenance product Steamer, but it doesn't replace a screwdriver or a wrench.

SeaFoam makes good products. You mention John Deer other than a couple of there units they are diesel engines, I have used it on my diesel as well, in fact I have stripped down the injectors and then run them, opened again and compared, I've seen the difference after running a can thru the high pressure pump to the rails then the injectors on the 6 lt.. It liquefied the both the diesel and oil gums that formed.

But that is all it did. It will also soak some, into carbon but not on its own remove it.

It has to be flowing to work.

As I've mentioned else ware it also cools combustion cycles because it burns slower especially at these compression ratios we run. It is unlikely to dissolve the plug in a jet has it can't flow thru it.

That takes a hot bath, poke and effort or replacement.

Remember also that mover carbs are single jet and air they are not staged. Each time the slide pluses a new path opens, path of least resistance wins

[videoarizona]

I'll add my .03 cents to this thread.

 

First, Seafoam is good but more as a maintainer, as has been mentioned. Techron is better if you want something to run in the tank. But good ole Carb cleaner works best to dissolve old crud in the passageways and jets of a carb. I use carb cleaner once in a while while bike is shut down. Techron example: My dealer wanted big bux to replace my spark plugs in the 6.2ltr GMC Denali. Just because of a simple miss fire code at startup. I came home and put some Techron in and about 200 miles, the engine light went away. Cleaned out those injectors nicely!

 

Second, If you are new to these V4's, Patch mentioned 5th gear as an overdrive...well... so is 4th! You can wind that motor up to the limiter without fear...I hit 75 in 3rd gear all the time. Lugging the beast won't clear the carbs. A simple saying we have around here to remember...every once in a while...put some Seafoam or Techron in the tank and ride it like you stole it. BTW, I don't shift to 5th until 70 to 75. I can get 41 mpg's on my 05 by staying in 4th gear....and holding 65 to 70 mph.

 

Bottom line, Get the carbs checked out. Check the tank for any kind of "stuff" that shouldn't be in there. Pull the fuel filter, replace it...and move it. It's in an awful place to get to. I put mine directly aft of the tank under the seat...in plain sight once the seat is removed. Do these things, then keep running it in 4th on the way to work. Take your time.....she will clear up most of the time. If not, then a carb removal is in order. That would be best, as you would be able to set the floats, clean the jets and would now know that you have a good starting reference point on the carbs.

 

On other thoughts... It's easy to check timing, check compression, pull plugs again and double check gaps. Do these things so you know what you have done.

 

Next time Seafoam or Techron is on sale, by a case. With this crap gas we have...they both come in handy. Add Stabil to that list for those times when you might not ride in a month.

 

Good luck and let us know what the dealer said and how the scoot is doing!

 

Oh..download the manual from the site.

Edited May 22, 2020 by videoarizona
add

[steamer]

Most of us agree it is a good maintenance product Steamer, but it doesn't replace a screwdriver or a wrench.

SeaFoam makes good products. You mention John Deer other than a couple of there units they are diesel engines, I have used it on my diesel as well, in fact I have stripped down the injectors and then run them, opened again and compared, I've seen the difference after running a can thru the high pressure pump to the rails then the injectors on the 6 lt.. It liquefied the both the diesel and oil gums that formed.

But that is all it did. It will also soak some, into carbon but not on its own remove it.

It has to be flowing to work.

As I've mentioned else ware it also cools combustion cycles because it burns slower especially at these compression ratios we run. It is unlikely to dissolve the plug in a jet has it can't flow thru it.

That takes a hot bath, poke and effort or replacement.

Remember also that mover carbs are single jet and air they are not staged. Each time the slide pluses a new path opens, path of least resistance wins

Actually JD makes a couple dozen products with gas engines. they have a large line of riding mowers, zero turns, and utv's.