Engine Stall .... Stumped?

[No_Longer_Active_User]

This is my second time taking my boat out and spent the day tubing.... The tank had some "OLD" gas in it (1/2 tank) and I topped it off and also added some gas stabilizer. The boat ran well for about 2.5 hours tubing...stopping and going....idling and shutting off and turning back on the boat constantly.....u know the drill when it comes to kids and tubing .... The problem began when we got down to about 1/4 tank of gas.... The boat started to "slow down" and the more I pushed on the throttle it just didn't seem to wanna go and then it stalled out.... I did get it started right away but could only drive it back to shore going 10 mph and when I tried to get the speed up...it would begin to feel like it was gonna stall or stop again. Any suggestions, comments or insight would be greatly appreciated.

 

[Lspeedss]

Fouled plugs

 

[Gym]

You may also have water in the old gas. I believe this is a new to you boat? Is the fuel from the previous owner? If my assumptions are correct you may want to consider draining the fuel and filling with fresh fuel. It's also common for a new buyer to put a boat into service if it starts and sounds good but the Yamaha's, at least, are pretty tempermental. They seem to like frequent spark plug changes. If YOU haven't done this you may want to do a plug, oil & filter change despite what the previous owner has told you.

 

[No_Longer_Active_User]

You may also have water in the old gas. I believe this is a new to you boat? Is the fuel from the previous owner? If my assumptions are correct you may want to consider draining the fuel and filling with fresh fuel. It's also common for a new buyer to put a boat into service if it starts and sounds good but the Yamaha's, at least, are pretty tempermental. They seem to like frequent spark plug changes. If YOU haven't done this you may want to do a plug, oil & filter change despite what the previous owner has told you.

Thanks for your input....I will definitely take it in on Tuesday and do just that, as far as the gas goes....it's a little less than 1/4 tank left so my next fill should be good!

 

[cane.mba]

I would drain the gas, and not add new gas until you've removed the old fuel. Check the label on your stabilizer, there is probably a recommended amount to add for stabilization, and there may be an increased amount you can add that will act as a fuel system cleaner. Also you may also want to check the fuel filter(s).

The issue you described would definitely be fouled plugs on a Yamaha, however, on a Sugar Sands I'm not sure. Wish we had more members with other jet boats.

Out of curiosity, were you in the ocean, or a freshwater lake?

 

[Murf'n'surf]

Change your spark plugs first. Start from easiest to hardest.

Long shot but....take a look at your impeller and shaft. Did you wrap a rope up in your drive?

 

[steined]

Does the boat have a fuel/water separator or "fuel filter" that looks like an oil filter? If so that could have too much water/separated ethanol gunk to allow enough fuel to pass. I had this happen on my Stingray 4.3 one time. I actually dumped the filter out into one of my zip lock bags because I was basically stranded and didn't have another filter. Then I disposed of it in an oil container when I got home. Not the ideal thing to do, but you can NOT dump that stuff into the water!

Did you get "pops" or noises while going WOT when it slowed down, or did it just bog down? This was also a sign on mine that it was time to change that filter.

 

[Gym]

Thanks for your input....I will definitely take it in on Tuesday and do just that, as far as the gas goes....it's a little less than 1/4 tank left so my next fill should be good!

@No_Longer_Active_User @cane.mba is correct. Do not add new fuel to the old. You didn't answer my question about fuel. Is it old? Has the oil and plugs been changed? If not you probably have water and gunk in the old fuel which will settle to the bottom of the tank. When you get out on the water this will mix with the good fuel and cause the same problem. I would spend the time and money now, at the beginning of the season, change the plugs, oil and filter and get rid of the old fuel. That way you will know what you have and what's been done. Then you can enjoy the summer.

 

[No_Longer_Active_User]

I would drain the gas, and not add new gas until you've removed the old fuel. Check the label on your stabilizer, there is probably a recommended amount to add for stabilization, and there may be an increased amount you can add that will act as a fuel system cleaner. Also you may also want to check the fuel filter(s).

The issue you described would definitely be fouled plugs on a Yamaha, however, on a Sugar Sands I'm not sure. Wish we had more members with other jet boats.

Out of curiosity, were you in the ocean, or a freshwater lake?

We are on the st. Lucie / Indian River..... Brackish Water, and I always hose down the boat and flush out the engine

 

[No_Longer_Active_User]

@No_Longer_Active_User @cane.mba is correct. Do not add new fuel to the old. You didn't answer my question about fuel. Is it old? Has the oil and plugs been changed? If not you probably have water and gunk in the old fuel which will settle to the bottom of the tank. When you get out on the water this will mix with the good fuel and cause the same problem. I would spend the time and money now, at the beginning of the season, change the plugs, oil and filter and get rid of the old fuel. That way you will know what you have and what's been done. Then you can enjoy the summer.

@Gym ... YES the fuel was pretty old.... sitting in the tank for about 7 months according to the seller and NO the plugs and fuel filter(s) have not been changed, so I will take the advice given and head down to the mechanic on Tuesday!
Thanks Again

 

[No_Longer_Active_User]

Change your spark plugs first. Start from easiest to hardest.

Long shot but....take a look at your impeller and shaft. Did you wrap a rope up in your drive?

Nope....no rope.....did that on my jet ski and learned my lesson! lol

 

[Lspeedss]

This thing has a single 4cylinder Merc engine correct?

 

[Magic]

7 months is not too terribly old for gas, and the water in the fuel thing thing should have caused problems right off since the water will layer below the fuel and get to the pickup sooner than later, and certainly sooner than the 2.5 hours you ran with no trouble......

I agree that spark plug are a good place to start, but also please check/replace the fuel filters. My instinct tells me that through sitting for 7 months, a bunch of crud may settled on the bottom, and running for 2.5 hours might have been enough time for that crud to make it to the fuel filter(s).....

Like I said its just my instinct based on experience, but its not a bad place to start...

Good Luck and please let us know what the mechanics find!

 

[No_Longer_Active_User]

This thing has a single 4cylinder Merc engine correct?

??.....it has a single 175 Merc engine

 

[No_Longer_Active_User]

7 months is not too terribly old for gas, and the water in the fuel thing thing should have caused problems right off since the water will layer below the fuel and get to the pickup sooner than later, and certainly sooner than the 2.5 hours you ran with no trouble......

I agree that spark plug are a good place to start, but also please check/replace the fuel filters. My instinct tells me that through sitting for 7 months, a bunch of crud may settled on the bottom, and running for 2.5 hours might have been enough time for that crud to make it to the fuel filter(s).....

Like I said its just my instinct based on experience, but its not a bad place to start...

Good Luck and please let us know what the mechanics find!

Thanks and will do

 

[Gym]

@No_Longer_Active_User. How are you doing with the stalling problem? I hope you're back on the water having fun with the kids. Let us know.

 

[itsdgm]

Does your boat have a fuel shut off switch? Possibly a main, reserve, off selection? I'm not sure how your boat is set up at all, but it's possible that you have a fuel pickup problem. I'd be tempted to put a few gallons in it to see if it just can't get the last 1/4 tank of fuel. Who knows? Maybe the fuel gauge isn't accurate either. That's pretty common on a lot of boats too. Maybe you're riding on fumes!!!

Edit. Can you see the tank to make sure there's fuel in there?

 

[No_Longer_Active_User]

@No_Longer_Active_User. How are you doing with the stalling problem? I hope you're back on the water having fun with the kids. Let us know.

@Gym
Received bad news today but going tomorrow for a second opinion..... The mechanic told me it isn't a spark plug problem...he said my engine has two bad rings/cylinders (but said they did ck the compression and that was fine).... Anyway, when I asked how much they said anywhere from $1500. - $2300. To rebuild these faulty cylinders!
I just bought the boat about 5 weeks ago and really can't believe this is happening....going for a 2nd opinion on Friday ... I'm completely bumbed out!

 

[No_Longer_Active_User]

Does your boat have a fuel shut off switch? Possibly a main, reserve, off selection? I'm not sure how your boat is set up at all, but it's possible that you have a fuel pickup problem. I'd be tempted to put a few gallons in it to see if it just can't get the last 1/4 tank of fuel. Who knows? Maybe the fuel gauge isn't accurate either. That's pretty common on a lot of boats too. Maybe you're riding on fumes!!!

Edit. Can you see the tank to make sure there's fuel in there?

I don't think it does have a fuel shut off switch....the mechanic I went to said the engines compression is good but 2 out of the 6 cylinders r bad

 

[No_Longer_Active_User]

7 months is not too terribly old for gas, and the water in the fuel thing thing should have caused problems right off since the water will layer below the fuel and get to the pickup sooner than later, and certainly sooner than the 2.5 hours you ran with no trouble......

I agree that spark plug are a good place to start, but also please check/replace the fuel filters. My instinct tells me that through sitting for 7 months, a bunch of crud may settled on the bottom, and running for 2.5 hours might have been enough time for that crud to make it to the fuel filter(s).....

Like I said its just my instinct based on experience, but its not a bad place to start...

Good Luck and please let us know what the mechanics find!

@Magic Received bad news today but going tomorrow for a second opinion..... The mechanic told me it isn't a spark plug problem...he said my engine has two bad rings/cylinders (but said they did ck the compression and that was fine).... Anyway, when I asked how much they said anywhere from $1500. - $2300. To rebuild these faulty cylinders!
I just bought the boat about 5 weeks ago and really can't believe this is happening....going for a 2nd opinion on Friday ... I'm completely bumbed out!