X-Star Problem...Please Help

Earlier this summer I took my boat in because it was making some bad noises and loosing power. Once you get over 1500 rpm's it starts making a clanking noise somewhere in the engine, looses power, and backfires out the carborator.

The dealership thought that it was the transmission, so they sent it off to Hurth Transmissions. Now they have gotten it back, and it is still doing the same thing.

Someone, please help. I would greatly appreciate any advice you could give.

Your boat shouldn't have a carb. What motor do you have?

I'm no expert but I am sure a bad tranny would not cause a backfire out the carb. Sounds engine/carb related to me. The clanking noise does not happen at 1200 RPM or 1000 RPM?

Yeah, your right. It doesn't have a carb. I don't know why they told me that. But they keep saying it is backfiring out the carb (don't know what that means). It is the indmar 310 hp vortec engine.

I think you can slightly hear the clanking noise while it is idling, but it gets loud the more throttle you give it.

Any ideas?

I'd find another dealership, and fast!! I was gonna say ignition is suspect for the power loss, but the clanking worries me, could be a thrown rod.

I had a similar problem in my Malibu once (350 MPI Merc). Backfires, no power, would idle rough, would die if over 2000 RPM, engine mad all kinds of noises I'd never heard an engine make. Ended up being an alternator wire knocked off from the terminal. I'd never thought to look at the alternator, but it sounds like your problem maybe just like the prob I had. I'd atleast check it, really easy to check and fix.

They already checked to see if it had thrown a rod - that's not it.

Jeff - Sounds like a good idea. I will have them check that in the morning. Before this starting happening I had a problem with the ignition module going out. Do you think those two things could be related (to the alternator wire)?

seems silly, but have you checked to make sure that your spark plug wires are installed in the correct order? Sounds like one is either disconnected or connected in the wrong firing order.

Hey Matt... how can you honestly feel comfortable dealing with that dealer when they tell you that it is backfiring out of the carb and there is no carb? YIKES. RUN FAR AWAY!!!

I think they meant out the throttle body. He knew there wasn't a carb because I asked him and he said there wasn't.

As far as the backfiring, have you eliminated the simple things? When you say that it does it after 1500rpms, is that in motion, or hooked up to a hose? The reason I ask is that it could be water sitting in your fuel filter that gets disturbed and run throught the engine once you put the boat into gear. Just a thought.

I second Johns suggestion that you check your firing order, esp. since you just had your ignition worked on. Not sure if that engine is distributorless or not, but if you have a distributor and plug wires I'd check it. It would cause all the symptoms you describe.

It's either crossed plug wires or your ignition pack is failing. The clanking is probably valve/lifter chatter.

Eric

Thank you so much for all your advice. The winning diagnosis goes to JohnE. The plug wires were out of order. You are a genius. Now, after two months of my boat sitting at the shop waiting for a rebuilt transmission, I finally get to take my boat out for Labor day weekend. Thanks again.

Thats awesome! Good work John. Not too awesome though that your dealer didn't catch it for you.

No kidding. Especially since I missed two months of riding (3 of those weeks which I had off and could have rode everyday).

The throttly body/injector housing on that motor looks a lot like a carb. I still don't think I'd call it a carb, but if you look at that motor it would be easily confused if you weren't that bright. Even the manifold looks like it's carbed. I'd definitely look at ign. problems. If you were getting misfires it could make some nasty noises, too.

Who put the spark plugs and wires on wrong?????? Or the wires that got crossed or whatever?????

The dealership never checked the spark plug wire order? and rebuilt your tranny? curious...

Matt, who changed your plugs and/or plug wires. If I am not mistaken it ran fine the first few times you had it out correct? Did this start after you had the ignition problem at horse shoe?

I am glad it is fixed now.

Yeah, some dumb mechanic at horseshoe lake screwed up the order of the plug wires when he changed the ignition module and cleaned the corrosion of the distributor cap.

Just got back from a great weekend at Greers Ferry, and the boat ran great! Thanks again John - the weekend would have sucked without your wisdom.

wow now that we have someone wiht great knowledge, lets see if you can please help me. It the oil guage that goes down to zero and once in a while the alarm goes off and it cuts out the stereo, it gets anoying, dealer cant seem to fix the problem. Ill appreciate your help, thank you

bad oil pressure sending unit

Loose earth/ground wire behind dash.

Is there an easy way to fix a fuel gauge that is stuck on full. As soon as you turn the key, the fuel gauge goes to full and stays there.

Matt, glad your boat is working and especially without paying a mechanic to tell you it was something major.

I had a friend whom loaned his boat to his brother. When his brother brought it back, the boat didn't work and a local boat mechanic said it needed a rebuild. The boat wouldn't fire. We ended up buying about $30 in ignition parts and the boat ran great for a couple of seasons before he lost it in the cali fires here a couple of years ago. It always pays to check the simple things first.

Matt

Take out the cooler under the back seat of the boat and you will see the fuel tank. One top of the tank there are two circular "units". On top of the smaller one (it was closer to the driver's side on my boat) there are two small "adjuster screws". They are used to make adjustments to the fuel gauge. Mine had a coating over them that I had to scrape off before I could get to the screws. Be careful when adjusting the screws. They are VERY sensitive. I would suggest adjusting them when you know how much fuel is left in the tank (I did mine when I knew I had used 1/2 of the tank). It will need a little fine tuning, but this should do the trick. Hope this works...let me know if you have any questions.