Getting really sick and tired of this finicky 2-stroke boat...

[scooper77515]

Took it out on the lake today, and ran tip-top 100% awesome for about 4 hours.

Then we start to get tired so we head back to the ramp, and about half mile off shore, it starts to lose rpms and run like crap, lots of missing, etc. I assumed it was a fouled spark plug since I am running 50:1 premix and riched up the oil injectors a bit. Been smoking a little all day, but not too bad, or any worse than any outboard.

Well, we idle in at under 3000 rpms to the ramp, pull it out of the water, pull the drain plugs, and oil comes out of the bilge.

I pop the hatch and the oil line was touching the exhaust pipe at the front and melted a small hole in it, but still half a tank of oil left.

Exhaust pipe has burned all the paint off.

No beeps, cheeps, or creeps before this.

In the garage and going out of town for the weekend, so won't have a chance to look at it til later.

Any ideas before I get in there?

Oil injection lines have no bubbles, and still plenty of oil in the big lines when I pulled it out of the water, so I am assuming it overheated for some reason, and then melted the oil line. So there should be no permanent damage, just a major mess to clean up and a little troubleshooting to find out why it overheated in the first place.

Only around 20 hours on this new motor.

 

[scooper77515]

Hmmm. Just pulled picture off my cell phone, and I notice that the pipe is only burned just behind the cooling hose.

I wonder if it got a clog in it somewhere.

Boat was peeing fine all day, but I didn't look when it started to run like crap.

 

[ProbeGT]

Hmmm. Just pulled picture off my cell phone, and I notice that the pipe is only burned just behind the cooling hose.

I wonder if it got a clog in it somewhere.

Boat was peeing fine all day, but I didn't look when it started to run like crap.

The last time I went on water I overheated my exausth pipe but I noticed it just before big mess happens. The reason it overheater was weeds, but I still had plenty of go so i tought the weeds were crushed by the impeller. Since the cooling water comes from the jetpump, eaxusth pipe overheated before the engine (quite bizzare actually).

I unscrewed the water regulator to add more water to the exausth to make sure it'd never overheat. now my red screws are flush with the top of the caps.

 

[scooper77515]

There were lots more weeds floating around than usual. I never thought anything of it. Just assumed the swirl would chew it up and spit it out. Will be tearing down and inspecting soon.

 

[Dr Honda]

OK... I know hindsight is 20/20... but did you check the temp sensor during the new engine install?

The blistered paint on the pipe is telling me that you lost cooling to the pipe. Hopefully, you didn't loose cooling to the jugs.

Let us know what you find.

Sorry you're having issues.

 

[scooper77515]

I didnt "check" it. Just swapped it over from old motor. How do you check it to see if it is functioning correctly?

Paint is only burned on last half of exhaust and ran fine at low rpms, and restarted easily on the trailer so i am guessing jugs and pistons are fine.

Popping the heads off to take a look asap and compression check.

 

[Chester]

It's your water regulator. Check for a plugged hose. Your engine will be fine.

Chester

 

[scooper77515]

I figured it would be a faulty regulator. Hope you are correct...

 

[Dr Honda]

I didnt "check" it. Just swapped it over from old motor. How do you check it to see if it is functioning correctly?

Get a pot of boiling water... hook a multi meter to the sender, and dip it into the hot water. You should see it go from an open to a short. (infinite resistance to almost 0)

Paint is only burned on last half of exhaust and ran fine at low rpms, and restarted easily on the trailer so i am guessing jugs and pistons are fine.

Popping the heads off to take a look asap and compression check.

I forgot we were dealing with a Challenger. As normall... Chester is right. The regulator probably isn't working, and wasn't' spraying water into the system.

 

[scooper77515]

It was working fine all day then just quickly got hot. Could this occur from sucking something up or was there crud in the system that finally worked its way around to clog it?

 

[scooper77515]

Would I be best off at this time to just rebuild and replace all the water regulator and hoses?

How do I adjust the water regulator when I am done, or should I just leave the red plug in the cap where it is?

 

[scooper77515]

I figured out why it wouldn't run well at high rpms...the rubber portion of the exhaust burned through so I was trying to run the engine on exhaust fumes.

Gonna start tearing it down and making a parts list.

 

[Dr Honda]

Well... that would do it.

At least you found the problem before running it again. BUT... the high heat is what burnt the tube. You are still laking water in the exhaust. You need to find the restriction, and clean it out.

I would recommend using compressed air, and blow back though all the hoses, and nipples.

 

[scooper77515]

Yeah, I am on my way out right now to disassemble and take stock in what I have. And start a parts list...

I need to find where the restriction was.

 

[scooper77515]

Looks like the water outlet into the exhaust at the very back, the calibrated fitting, was plugged.

Pulled the line off the engine and 2 cups water came out. Everything else seems to be able to be blown through and other than melted hoses and burned paint, I see no other problems.

 

[scooper77515]

Well, I got it back up and running...

Before and after pics attached.

Pulled the exhaust and found all the water lines were melted, both oil lines to crank, lots of smoke and soot.

Repainted the exhaust, new gaskets, drained engine and oil tank of $90 BRP XP-S oil and put a gallon of Mystik in there. Got it all back together and it started right up, ran about 5 minutes on the hose and all the correct hoses were bubbling with water, and peeing out back. :hurray::hurray::hurray:

Muffler was warm, but could easily put my hand on it and leave it there.

So, hopefully, it is ready for a water test.

Raining today, got our handicapped twin neices for the next two days, a date in houston for my birthday on saturday, a date with my parents on sunday, so next chance for water is next week after work one day, or next weekend.

Maybe sunday afternoon, if the weather cooperates.

Wish me luck...:cheers: