Blew b pipe coupler, now performance is terrible... FIXED.

joshuaeric

joshuaeric

X
Location
Santa Barbara, CA
I recently blew a coupler to the point where the b pipe was disconnected from headpipe, and the water was flowing straight into the hull from the headpipe. Oddly enough, the ski still ran with this condition (albeit a small decrease in performance all around) just with a much louder sound than usual (which is what gave me the indication that something was not connected properly). I have a front exhaust connection.

Ordered a new coupler, and my mid to top speed is pretty much completely gone and my bottom end power ranges from 30-50% of what it used to be.

I then noticed that the elbow between the b pipe and the water box was leaking exhaust into the hull along with water.

I fixed that and the performance hardly increased at all, boat will barely plane off, and will reach about 30mph with the throttle pegged.

I then replaced the plugs, which had zero effect.

Things I have done to fix the problem:

Adjusted high speed screws (did change the attitude of the engine)
Adjusted low speed screws (did change the idle of the engine)
Adjusted the top water screw on the pipe (no change in performance)

I am going to hook up with a friend tomorrow and start tearing it down. First thing I am going to check is compression.

Anyone have any suggestions? Would riding basically without a coupler on my pipe ruin anything specifically?

Specs of the ski are in my signature.
 
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Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
Before you tear anything down, do the basics.
Got spark?
Got fuel?
Got compression?

Next, ride with the hood off (carefully). Is it better? If so, you've got an exhaust leak.
I have a hard time believing that you had very little performance decrease with a blown coupler. That is a major exhaust leak and usually leads to the engine shutting down/choking itself in short order.
 
WFO Speedracer

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
I think you still have an exhaust leak somewhere,I would not suggest riding with the hood off though,try this instead. With the ski out of the water and the hood on,fire it up and rev it up several times for a few seconds,now pull the hood off,if you see any smoke at all then you have an exhaust leak.
 
joshuaeric

joshuaeric

X
Location
Santa Barbara, CA
sflsurfrider said:
sooooo, that new coupler that you ordered.... did you put it on yet?
Click to expand...

I know right?

The ski isn't make any sense at this point.

Rides the same way with the hood off. There is no exhaust leaking into the hull at this point. I've replaced every exhaust hose from the manifold back and triple checked the connections, even going as far as replacing the hose clamps.
 
joshuaeric

joshuaeric

X
Location
Santa Barbara, CA
Matt_E said:
Before you tear anything down, do the basics.
Got spark?
Got fuel?
Got compression?

Next, ride with the hood off (carefully). Is it better? If so, you've got an exhaust leak.
I have a hard time believing that you had very little performance decrease with a blown coupler. That is a major exhaust leak and usually leads to the engine shutting down/choking itself in short order.
Click to expand...

Compression is my next check, my buddy has the proper tool to do so.

To clarify with the coupler, if I wedged the pipe up against the headpipe, it would run. If it fell down completely off, it would die almost instantly (do to exhaust fumes).

So it was enough on to where exhaust would go through the pipe, but water would still leak into the hull.
 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
Stuff like this is frustrating, especially at the height of summer.
Hang in there, you'll figure it out.
 
djkorn1

djkorn1

kidkornfilms
Site Supporter
Location
Cleveland Ohio
Doesn't sound good. Sounds like the engine blew and took the coupler out with it.

Ps....I ride with my hood off all the time to check stuff out! Bunch of chickens! :highhorse:
 
Mark44

Mark44

Katie's Boss
Location
100% one place
Yep I have done the hood off rides many times to find problems.

Do not go jacking with the carbs if it ran good before this issue, they didn't mysteriously get out of tune.

Sounds like a melted piston to me also need that compression check.

Mark44
 
joshuaeric

joshuaeric

X
Location
Santa Barbara, CA
Good news.

Checked compression, was spot on identical in both cylinders.

Removed head, everything looked flawless.

As I was standing there, my buddy steveowe was messing with the throttle while leaning over the hull and noticed something funny.

The butterfly on one of my carbs was not moving at all...

Tightened the allen wrench screw on the linkage and boom, she runs fine again.

I don't know how or why the coupler going out coincided with the screw becoming loose, being they are on different sides of the motor and seemingly unrelated, but anyways, it is what it is.

I put my carb screws and pipe screws back to where they were previously (always write down known good settings on a piece of paper you know you will keep), and she performs flawlessly again.

I had a new top end priced out and carb rebuild kits. At the end of the day, all it took was a quarter turn of an allen wrench screw. And yes, with a little dab of locktite.

And now I can ride for the entire weekend of the 4th; special thanks to Steveowe and his very timely diagnosis.

Two heads are always better than one.
 
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WFO Speedracer

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
joshuaeric said:
Good news.

Checked compression, was spot on identical in both cylinders.

Removed head, everything looked flawless.

As I was standing there, my buddy steveowe was messing with the throttle while leaning over the hull and noticed something funny.

The butterfly on one of my carbs was not moving at all...

Tightened the allen wrench screw on the linkage and boom, she runs fine again.

I don't know how or why the coupler going out coincided with the screw becoming loose, being they are on different sides of the motor and seemingly unrelated, but anyways, it is what it is.

I put my carb screws and pipe screws back to where they were previously (always write down known good settings on a piece of paper you know you will keep), and she performs flawlessly again.

I had a new top end priced out and carb rebuild kits. At the end of the day, all it took was a quarter turn of an allen wrench screw. And yes, with a little dab of locktite.

And now I can ride for the entire weekend of the 4th; special thanks to Steveowe and his very timely diagnosis.

Two heads are always better than one.
Click to expand...


MY 550 DID THAT ONCE AND YOU ARE RIGHT IT RAN QUITE ********TAY:biggrin:
 
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