More problems... Great any of you gear heads have any ideas

Well temps warmed up alot today so I went to the lake and decided to start the boat and thoroughly check everything to make sure I'm ready for the season. Well I started the boat and it ran fine fIne for a bit until I began to accelerate. Around 2500-3500 rpm the motor started surging really bad almost like it was missing and it would not accelerate past that point. At that point I noticed the check engine light was on so I headed back to the dock. I stopped my boat and opened the hatch and soon as I did I heard a fairly loud pop. Almost sounding like the popping of a ziplock bag full of air and then the really large hoses running from the motor to the muffler started to contract and expand. I thought maybe it released pressure or possibly fixed the problem so I re started the motor and revved it in neutral and it seemed great for a few minutes even at higher rpm and then it started again... Any ideas?

Mason,
Call Brian Kruer and ask him. I know he did all his own mxc on the boat I bought from him. He may know more about what hoses go where. Who winterized your boat last Year? You may have crossed two of the hoses when you or they hooked them back up. I would doubt that the problem fixed itself. Any temperature rise like it wasn't getting water?

Sounds to me like a Fuel System problem. Did you put Fuel Stabilizer in to winterize it? Also check your air filter going to the intake!

Thanks David. Kruer was actually the first person i called too! He had no idea haha. Boatworks did the winterization other than stabilizing the fuel, disconnecting batteries and oil change which I did all of myself. Yea I checked the temp and I was just where it was supposed to be.

Sounds like a miss or that it is starved for fuel. Mine did that last year, and it was due to some moisture in the tank. Try some heat in the gas.

Heat in the gas?

Sounds like to me that you had no cooling and engine went into limp mode. Double check impeller but more importantly make sure you are not sucking in air around connections to the pump.

Yea the engine temp never even got slighty high. Bow that I think about it though I did have th change the fuel filter last week. Maybe something didn't hook back up right?

Run it on the trailer with a hose make sure there is water coming out the exhaust.

Mason Heat is a product you buy at autozone to remove moisture from fuel. Did you store it with a full tank of gas? If not over half full you may have some condensation. It could have been just air in the fuel lines from the filter change.

Plastic fuel tanks do not condensate - metal does. It is a myth to store with a full tank of gas

I think that every DIY mechanic needs to own a fuel pressure gauge. You can get an Actron CP7818 for about $35 on Amazon. It is as easy as hooking it up and putting the engine thru a couple test phases to know what you problem is.

At this point you are just taking shots in the dark by replacing parts. Could be a fuel filter, could be a fuel pump, it could even be that you have corrosion in your distributor cap.

So it would have to be a problem in the fuel system? How does that explain the hoses collapsing (sucking in and out on their own)? No one else thought that it was wierd?

Not necessarily.

The hose between the heat exchanger and the muffler is pretty heavy duty stuff so I am surprised that it was able to expand and contract. Have you shined a flashlight in the exhaust outlet to see if there is a potential blockage. Go to the rear of the boat, lift her skirt up and sign that flashlight into that black hole.

yea it was totally unblocked/free and open. I hope a bird didnt make a nest way up in there

I'm no expert but condensation comes from the moisture content in the air. If your tank is full of air it can condensate weather it is plastic or not. I did not realize what you said about the large exhaust hoses expanding and contracting. I would call the guys at boatworks and ask just in case. Maybe try to run it on the trailer where you can keep a close eye on everything.

Dave - no worries. I used to think the same thing after doing some research. http://www.yachtsurvey.com/myth_of_c...fuel_tanks.htm

The minute amount of condensation you may have is not going to do any harm especially if you run stabil. My boat stays winterized for about 8 months of the year and I siphon the gas out at the end of every year. Never once had a problem with condensation and every season I get to put a fresh tank of gas in it.

Mason - What temp are you seeing? 160, 180 or 180+

honestly I didnt read the number but it was at the 1st hash mark after running the boat for around 20-30 minutes never got even close to being high

Pretty good checklist right here.

http://www.skidim.com/Faq_TROUBLESHOOT.asp#RWTS

Actually Mercruiser recommends to store or lay up as they call it, with full tank of fuel with stabilizer added unless the fuel has alcohol, then they want it drained as far as possible and still add stabilizer. Straight out of the Merc shop manual.

So I think maybe the problem has something to do with my batteries not charging. I took the boat to the shop last week and they noticed the batteries were low so they put them on a charger and took the boat and ran it. They could not get the boat to act up again but said the voltage meter was running sub 12v. So I ran the boat on the trailer again no problem for several minutes and put it up. Well I got the boat out again today and it ran fine for a bit
And started the same problem all over again. After i turned it off it would not turn back over and the accessories one by one died off which makes me think the probl is low voltage. So my question is can low voltage send the boat into failsafe or protect mode or cause any of the problems i described? I replaced the alternator cable that was badly corroded but it still isn't charging. And I'm guessing the problem may be the alternator which i just got a new one last fall.

Low voltage can cause issues with the ECM. It's also hard on the charging system to bring very low batteries back up by running the boat. This can also cause spikes that the ECM doesen't like either but yeah low voltage can cause drivability issues. No diagnosis can be done without first having fully charged batteries and a working charging system.

Yes, low voltage could be the exact symptoms. Mine did. I added a 2nd battery and all good. Test that alternator.

Hook up a voltmeter and watch charging system voltage. You should see 13+ volts. Anything under 11 and you're going to cause all sorts of running problems. Might even see those problems with closer to 12 volts. Fully charged batteries should show 12.6v.

You might also not be getting correct water circulation. If you don't have water by your temp pick-up, then you wont see accurate engine temp. Those pick-ups need water circulating around them to actually tell you engine temp. Check your impeller and hose routing. Also, make sure your impeller is turning. They can stick and the belt will slide on the pulley. I've seen it before. Sometimes they don't even make noise.

Steel fuel tanks definitely need to stay full. Plastic is not as critical. It's a big function of rusting internally where there is small amounts of air and moisture. Personally I'd still prefer to keep my tank full over the winter. Add some stabil when it sits for more than 3 months.

Mason,
It sound like your batteries ( as you have described are not holding a charge or not being recharged by the Alternator). If you are running your engine for a while and then when you turn it off it is not restarting then that is definitely a charging system problem. Sometimes a bad starter can drain your battery as well. I had this happen in my 2001 Supra SSV. Batteries were not holding a charge , Alternator was bench tested and was fine, and it came down to a bad starter that was constantly draining the battery.
It may be another road to go down if you dont find anything else wrong with it.
Hope you get it figured out soon. Summer is coming quick!!!

Problem was a bad alternator. Getting it fixed now. When batteries were extremely low it was causing the problems. Not sure how it caused the exhaust popping but alternator was only putting out 10 volts

With the voltage that low the ignition system was likely not able to fire the spark plugs properly, leading to fouled plugs and unburnt fuel in the exhaust. The popping was probably from that fuel combusting in the exhaust after the plug cleaned up enough to fire.

Yea that's what I was thinking but a few people told me I was wrong. Should I changes the plugs now or should they be ok? Also the alternator was fairly new. I installed it as an upgrade last year with my sub and wetsounds. The power wire to the started actuality touched the block and arced. Could that have been what fried it?

Originally Posted by superair502

Yea that's what I was thinking but a few people told me I was wrong. Should I changes the plugs now or should they be ok? Also the alternator was fairly new. I installed it as an upgrade last year with my sub and wetsounds. The power wire to the started actuality touched the block and arced. Could that have been what fried it?

It's possible that you cooked the voltage regulator in the alternator when it arced since it can't handle that kind of current.

You could run on the current plugs but since they have been fouled they are more likely to have misfire issues in the future. You can take them out and give them a good cleaning (brake cleaner and/or propane torch on the electrode), but once they are out you may as well throw in a fresh set since they are inexpensive and won't be a question in your mind later on.

Just make sure your alternator issues are all fixed before changing the plugs so that you don't waste your time and ruin another set.

Thanks guys voltage regulator on the alternator was fried. New one installed and the boat runs like it is brand new!