Power Fluctuations

[mick11]

Never had any real time to work on the boat. They aluminum carb bolt have been rounded off by the previous owner. It's making it harder than originally thought. I will check out a local boat dealer to see if I can by new bolts.

Another person suggested that i should have run the boat with the gas cap off. If the fuel tank vent was clogged, it could cause a surge as well. I wish I though of that before I took the boat apart.

 

[kustomkarl]

Chances are that the vent line isn't the problem. You could go to West Marine or similar marine store for bolt replacements. Remember they are metric.

Karl

 

[mick11]

10mm to be exact. i will bring one of the bolts in to ensure I get the exact replacement.

Going to Sears Hardware to get a 10mm uni-wiggle 1/4" drive as some of those bolts are tucked away.

 

[luv_my_grlz]

Update (Status & Questions)

Morning all!

We finally had a chance to take the Sportster out on Thursday after mick11 replaced the fuel lines and cleaned out the carbs. It ran much better (see below for details) but still not anywhere near "right".

1. Getting longer "good" runs at 6,000 rpms.

2. When the rpms drop, the drop is a lot shorter in duration than it used to be (mostly momentary) and for the most part they are only dropping to around 5,000 rpm as opposed to 4,000 rpm before mick11's work.

3. We can now go full throttle. It runs very rough unless you apply choke, but at least it doesn't die at full throttle like it did before.

4. We can make sharp turns without dying. Again, it runs very rough, but at least it's not dying.

Our thought at this point is that at least we know we are kind of on the right track. Mick11 was thinking it might be best to just completely replace the carburetors since it looks like somebody monkeyed with them a lot. But looks like sbtontheweb only carries the rebuild kits.

What do you guys think?

Thanks,
luv_my_grlz

 

[luv_my_grlz]

An idea?

One more thought guys (sorry for multiple posts).

Could it be at this point that the carbs just need to be properly adjusted for the correct fuel/air mixture? Is there a guide for how to accomplish that?

Thanks!

 

[kustomkarl]

You could be sure the carbs are adjusted properly. The low speed screw should start at 1 1/2 turns and the High speed screw is at "0" with the plastic cap on it. When you cleaned he carbs did you ever check the pop off pressure of the carb? Was the tang on the needle and seat level to the carburetor area? Be sure the oil injector is adjusted in sink to the carburetor cable if you adjust the cable. Use the idle screw to adjust the idle not the low speed screw. It might be that the carbs need to be tuned as it sounds like its getting close. Let us know how you make out.

Karl

 

[mick11]

Didn't get to check pop-off pressure. The two screws holding in the plate are rounded out. Previous owner should have his tool priveleges revoked. Need to get those removed and replaced. I was hoping that SBT would have re-man carbs that I could order. Be nice to have a clean slate as I have no idea what other surprises the previous owner left for me.

The tang was level with the carb.

Will try adjusting the carb settings soon.

 

[kustomkarl]

Usually if the tang is level it is close to the correct level it should be for the pop off. Give the carbs a tweak and let us know.

Karl

 

[Gunsrunner]

Couple of articles that might help,
http://www.sbtontheweb.com/forum/showthread.php?t=13965
http://www.sbtontheweb.com/forum/showthread.php?t=12015
http://www.sbtontheweb.com/forum/showthread.php?t=29016
http://www.sbtontheweb.com/forum/showthread.php?t=12004

Let us know how you go!!:cheers:

 

[mick11]

Thanks for the links gunsrunner.

I think those are very good videos. Should be a post sticky.

Mick

 

[luv_my_grlz]

Adjust one or both?

Hi All,

Suspecting the need is to adjust the high speed screw on the carb(s), we were looking at it this past weekend and only found the screw on one carb. So does the one adjustment control both carbs? Or, do we need to look harder for the screw to adjust the second carb?

Thanks!

 

[timmyboy76]

hsa...

Think i'd look a little harder...

 

[luv_my_grlz]

Clarification?

So, are you saying that there DEFINITELY is another adjuster on the second carb and we need to find it? Or you're just thinking there *might* be one, and you would recommend that we double-check for it? Please clarify (sorry, you gotta spell things out for me, ha ha).

Does anybody know for sure on this?

Thanks!

 

[timmyboy76]

You would think, with dual carbs, from ealier models..yah, 2 adjustments, but look'n at diagram, tells me different for your boat,....I shouldn't be so quick to shoot...Just thinkn initially, that screw is small, the cap might've been off