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m&m

developed a miss

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m&m

pulled the boat out, set up the fake a lake and ran the engine. everything looked and sounded fine. came up to 160 degrees, could see the thermostat open and control temp. after about 5 minutes. the boat starts a distinct rock to it. the engine has a miss. could not see anything wrong. water was coming out the exhaust and it did not over heat at all. it has not been ran in 6 weeks. i did not winterize the engine. i just pull it out and run it every month or so. any thoughts or suggestions on this issue?

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Greg_S

Clogged injector, bad gas, plug wire or related connection.

Warranty run to the dealer if it isn't obvious.

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Captain Blood

Mike, Sorry to hear this.

Was the boat protected from the cold, no chance of freeze?

Sometime intake gaskets won't leak until the engine gets to temp.

Check the distributor cap for moisture or a crack on the inside, if it does have a crack you will see some evidense of arcing going on inside.

Fuel filter?

Just trying to throw out some ideas.

Good luck

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RTS

Try disconnecting the electrical lead to each fuel injector one at a time to see if you can isolate a bad injector. Then I'd do the same thing to the spark plug wires.

Actually, I'd start with the spark plug wires.

If it's nothing obvious, this may be a good time to go to the dealer for some warranty work, as they are most likely not too busy this time of year.

The good news is that by running it every month or so, you've discovered the problem now instead of the first week of the season.

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Pistol Pete
Try disconnecting the electrical lead to each fuel injector one at a time to see if you can isolate a bad injector. Then I'd do the same thing to the spark plug wires.

Actually, I'd start with the spark plug wires.

I'd stick with un-plugging the injectors. If you disconnect the spark plug wires at the plugs without doing something to control the voltage that's gonna come out of there, you're gonna have a headace after you hit your head on the engine cover.

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Madmanacrossthewater

Morse often than not, it's a fuel filter. It's an inexpensive place to start.

Good luck !

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maliboo

M&M - The problem with unplugging any of these components is that these motors have what is called "spark stabilization". At idle you will not be able to tell any differance. When I went to the Indmar school we took a running Monsoon and started pulling plug wires off, there was now noticable differance until we had 4 wires off. Same goes for injectors. Now under load you will be able to tell, but that would be scary trying to pull stuff off while the boat was under way.

Stick with the basics. If it ran fine before it is likely to be something very simple.

Do you have a Hammerhead? You sure it has enough gas in it? Sounds like it is trying to run out.

Another thing that I have seen is a cracked insulator on a spark plug and for some reason that arcing to the block made it idle rough. Its hard to diagnose because it has to be very dark when you fire it.

Dwayne

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jetskipro550
M&M - The problem with unplugging any of these components is that these motors have what is called "spark stabilization". At idle you will not be able to tell any differance. When I went to the Indmar school we took a running Monsoon and started pulling plug wires off, there was now noticable differance until we had 4 wires off. Same goes for injectors. Now under load you will be able to tell, but that would be scary trying to pull stuff off while the boat was under way.

Stick with the basics. If it ran fine before it is likely to be something very simple.

Do you have a Hammerhead? You sure it has enough gas in it? Sounds like it is trying to run out.

Another thing that I have seen is a cracked insulator on a spark plug and for some reason that arcing to the block made it idle rough. Its hard to diagnose because it has to be very dark when you fire it.

Dwayne

I think that we have just found another great source of information if anyone has problems with their engine Yes.gif

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maliboo

Thanks Jetski - even though I went through a week with Indmar and a few days training in Merced, I was never a full time mechanic. I was just learning as much about the boats as I could to sell them better.

At the shop where I worked we were selling 70 boats a year with just me and the owner, so I got to see alot.

I can only talk about things that I have seen first hand. A real mechanic or Peter are going to know more.

Dwayne

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MoonDawg
M&M - The problem with unplugging any of these components is that these motors have what is called "spark stabilization".....Dwayne

What is that?? Sounds like some marketing hype...let me get my boots. Biggrin.gif

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maliboo

OK Moondawg, just for you I pulled out my 1997 Indmar Service Manual and notes taken during the class from Nov. of 1997, I can't believe that was almost ten years ago. It appears that "spark stabilization" occurs when the running engine is anywhere above 300 RPM's and to smooth out cold start-up. After looking though my notes there are alot of things that happen between crank mode 175-200 RPM's and Run mode 300+ RPM's. I remember it very well because it was a powerful demonstration on how effective the fuel and ignition system were. Try it on your car or boat, if your still awake after you grab the spark plug wire, see if the idle is noticably different. Surprised.gif

I looked at your gallery! Is that your boat? Holy SHA8 what happened? I will gladly donate my Indmar service manual, Malibu service manual and notes if you are trying to get that wreck back together. That engine with the Cutler FI was the first one I ever worked on. If you are looking at parting the boat I may be interested in the complete motor and related electronics. It would make a great car motor. I am not in the business any longer so I don't need the manuals.

Dwayne

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maliboo
M&M - The problem with unplugging any of these components is that these motors have what is called "spark stabilization". At idle you will not be able to tell any differance. When I went to the Indmar school we took a running Monsoon and started pulling plug wires off, there was no noticable differance until we had 4 wires off. Same goes for injectors. Now under load you will be able to tell, but that would be scary trying to pull stuff off while the boat was under way.

Stick with the basics. If it ran fine before it is likely to be something very simple.

Do you have a Hammerhead? You sure it has enough gas in it? Sounds like it is trying to run out.

Another thing that I have seen is a cracked insulator on a spark plug and for some reason that arcing to the block made it idle rough. Its hard to diagnose because it has to be very dark when you fire it.

Dwayne

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BillFooter

One of the less intellegent Malibu owners at our lake had Sunset Bob in his boat. Sunset Bob is a very good mechanic and noticed that the engine was misfiring. They stopped and opened the engine hatch. Sunset Bob says "Here is your problem, you have a missing spark plug wire" The not so smart boat owner says " Oh yeah, I put that on my pick up truck back in the winter and forgot to put it back on the boat engine." He had run the boat without one plug wire for about a month and had not noticed it running poorly.

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Sunset_Bob

It's very unlikely for a injector to just go bad from sitting 6 weeks. Cars can set for months without ever starting and not have injector problems. Most injectors out last the engines. I can count on one hand the number of defective injectors we have replaced that just went bad. Zero. Injector failure is from foreign material getting in the fuel system 99% of the time. If you do suspect a certain injector you can swap with another cylinder and see if you miss moves rather than just changing parts.

Whats the fuel pressure? Low fuel pressure can starve the last few injectors in the fuel rail and cause a miss or rolling idle.

I would must ask how cold it gets in your area? If you didn't winterize the boat, could it have frozen? A cracked cylinder head could cause a missfire and with a wet exhaust you wouldn't notice any difference in the water out the exhaust.

Do you hear any lifter clatter? Like a lifter that has lost it's prime? It could cause a misfire and usually will cure itself from higher rpm running a few moments. This is very common from engines setting for extended times. Salvage yard engines are notorious for collapsed lifters and take several minutes of extreme revving at higher rpms to dispell the air out of them sometimes.

It is possible for a spark problem but unlikely if it was running fine when you set it up. Unless it has rained in the boat or moisture was able to get under the engine cover. The cap could have sweated. If this is the case some good old WD-40 sprayed inside the cap will cure that.

Regardless of what anyone says, you should be able to pull the plug wires off the cap one at a time at idle and isolate which cylinder is misfiring. Just watch the tach as you pull them off and watch for a rpm drop. If no drop is noted on any individual wire, thats the cylinder thats not contributing in the firing order. Check for spark at the plug end of the wire and then remove the plug and check for the plug color and condition. If its wet, dry, oily, carbon fouled, etc...

A little common sense diagnosis goes a long way.

Hope this helps, if I was closer, I"d offer to help you find it for a pull. ;)

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m&m

sory for taking so long to get back. here is whats happening. brought the boat to the shop for some other warranty items and had them run the engine. no miss to be found at any rpm. the maechanic thought that i may have loaded it up revving the motor. not sure about that. but no miss. taking her out tomorow to see if all the other items have been addressed properly. thanks for all your input every one.

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MoonDawg
OK Moondawg, just for you I pulled out my 1997 Indmar Service Manual and notes taken during the class from Nov. of 1997, I can't believe that was almost ten years ago. It appears that "spark stabilization" occurs when the running engine is anywhere above 300 RPM's and to smooth out cold start-up. After looking though my notes there are alot of things that happen between crank mode 175-200 RPM's and Run mode 300+ RPM's. I remember it very well because it was a powerful demonstration on how effective the fuel and ignition system were. Try it on your car or boat, if your still awake after you grab the spark plug wire, see if the idle is noticably different. Surprised.gif

I looked at your gallery! Is that your boat? Holy SHA8 what happened? I will gladly donate my Indmar service manual, Malibu service manual and notes if you are trying to get that wreck back together. That engine with the Cutler FI was the first one I ever worked on. If you are looking at parting the boat I may be interested in the complete motor and related electronics. It would make a great car motor. I am not in the business any longer so I don't need the manuals.

Dwayne

The boat is a hurricane Katrina victim! I put a bid on it to get the engine as a spare. You can never have enough engines laying around Biggrin.gif Someone outbid me so it is still out there somewhere. I dont think that it will ever be used as a boat but the engine/transmission and running gear could be useful in some other application.

I would love to see your manuals. I am really trying to get a hand on the fuel injection system and so far the material I have found is pretty sketchy. Just a loan of your material would help me a lot.

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maliboo

Moondawg - let me know how I can get them to you.

What would great is if someone would scan all of it and post it in the tech section as a PDF. They could get all the manuals and do it.

Dwayne

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MoonDawg
Moondawg - let me know how I can get them to you.

What would great is if someone would scan all of it and post it in the tech section as a PDF. They could get all the manuals and do it.

Dwayne

I was planning a move like that...a section at a time. Do you think someone might get tweeked as far as copyright?

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