Engine cuts out after sharp turn or a lot of waves

[WeekendCruise]

Hello all, first i want to say thanks for all of the people on here that take their own time to give advice & suggestions. Saving people a lot of time, money and giving them some experience.

On to the issue.. At the beginning of summer i bought a 94' 19ft Caravalle Cuddy cabin. It has a 3.0LX Mercruiser with Alpha One out drive. This season the following work has been done (by a mechanic). New bellows, u-joints, gimbal bearing, lower **** cable (all due to bellow leak from previous owner), oil change, plugs & wires, ignition switch, starter, bilge pump & 2 new batteries. Also a few bottles of Sea-Foam & marine stabil. (I've read some of the debates on here about both those products, my mechanic said it was good stuff so i used it. good or bad, who knows.)

After working out all of the above kinks the last 3 times i've used the boat it works well. About 15 hours. Tops out around 32mph with 2 people, gear and full tank of gas. About 4500RPM WOT. Seems to get great mileage (for a boat).

Anyways, the last two times i've had the boat out, the engine has cut-out momentarily at high rmp. One time was after making a sharp turn, the next time it was after going over some bumpy waves & wakes for about 5 mins. The RPM's jump up and down until i slow it down.. when i open it back up right after it does the same thing. It will reach top rpm then slow down, and back up erratically. After the boat goes slow for a while or sits shut off for a few mins, the problem seems to go away again for a while. I've probably put about 70 gallons of fuel in it this summer, so i dont think it's bad gas. I'm thinking a fuel issue somewhere..? But not positive what it could be.

Thanks.

 

[alldodge]

Hello all, first i want to say thanks for all of the people on here that take their own time to give advice & suggestions. Saving people a lot of time, money and giving them some experience.

On to the issue.. At the beginning of summer i bought a 94' 19ft Caravalle Cuddy cabin. It has a 3.0LX Mercruiser with Alpha One out drive. This season the following work has been done (by a mechanic). New bellows, u-joints, gimbal bearing, lower **** cable (all due to bellow leak from previous owner), oil change, plugs & wires, ignition switch, starter, bilge pump & 2 new batteries. Also a few bottles of Sea-Foam & marine stabil. (I've read some of the debates on here about both those products, my mechanic said it was good stuff so i used it. good or bad, who knows.)

After working out all of the above kinks the last 3 times i've used the boat it works well. About 15 hours. Tops out around 32mph with 2 people, gear and full tank of gas. About 4500RPM WOT. Seems to get great mileage (for a boat).

Anyways, the last two times i've had the boat out, the engine has cut-out momentarily at high rmp. One time was after making a sharp turn, the next time it was after going over some bumpy waves & wakes for about 5 mins. The RPM's jump up and down until i slow it down.. when i open it back up right after it does the same thing. It will reach top rpm then slow down, and back up erratically. After the boat goes slow for a while or sits shut off for a few mins, the problem seems to go away again for a while. I've probably put about 70 gallons of fuel in it this summer, so i dont think it's bad gas. I'm thinking a fuel issue somewhere..? But not positive what it could be.

Thanks.

Think you have a fuel supply issue going on, and my first suspect would be the fuel pump. Go get a vacuum fuel pump pressure gauge. Put the gauge tee'd inline between the fuel pump and the carb.

http://www.harborfreight.com/fuel-pu...ter-93547.html

Also pull your filter and poor contents is something clear to see if you find anything.

 

[WeekendCruise]

Think you have a fuel supply issue going on, and my first suspect would be the fuel pump. Go get a vacuum fuel pump pressure gauge. Put the gauge tee'd inline between the fuel pump and the carb.

http://www.harborfreight.com/fuel-pump-and-vacuum-tester-93547.html

Thanks, would i need to cut the fuel line somewhere to add a T to be able to check the pressure with this tool?
Also, the filter is located directly on the fuel pump it's self right? Spring loaded? (Just from scrolling through other fuel related issues on here)

The boat seems to work OK before being shook around a little. (Not doing anything crazy)

Thanks for the reply.

 

[alldodge]

Thanks, would i need to cut the fuel line somewhere to add a T to be able to check the pressure with this tool?
Also, the filter is located directly on the fuel pump it's self right? Spring loaded? (Just from scrolling through other fuel related issues on here)

The boat seems to work OK before being shook around a little. (Not doing anything crazy)

Thanks for the reply.

NO, don't cut the line. The easiest way is get some rubber fuel line and some barb fittings from the auto or hardware store. Replace the steel fuel line with the rubber for testing. Or, disconnect fuel line from the carb end and connect some rubber fuel line to it with a hose clamp. Then put a tee and another fitting to reconnect to carb. Pressure should be between 4-7 psi.

Pull the fuel bowl off the bottom of the carb and catch contents in something and have a look.

 

[keith2k455]

You may also want to check the float level and fuel water separator if equipped

 

[airshot]

Yep... I will second those suggestions but like to add that if you do not have a water separator/ filter do add one. You may have some water in the fuel that gets sucked up when bouncing over waves or in hard turns so check your fuel carefully. Many recent posts about water in gas from vent line so check your as well.

 

[funk6294]

For sure could be caused by a little water built up in the separator. Sounds like it otherwise runs well. I would start by checking/changing the filter. Here is a video where some did one.

 

[WeekendCruise]

Yep... I will second those suggestions but like to add that if you do not have a water separator/ filter do add one. You may have some water in the fuel that gets sucked up when bouncing over waves or in hard turns so check your fuel carefully. Many recent posts about water in gas from vent line so check your as well.

The vent works.. when i fill the gas tank air does come out.. is there something else i should check that for? I was wondering if it could be water as well.. Going to be taking it to the Allegany Reservoir in PA this weekend. I will attempt the fuel filter change, as well as inspect all fuel line connections ect. I didn't see a water separator, i'm going to attempt to add one of those also.

 

[WeekendCruise]

For sure could be caused by a little water built up in the separator. Sounds like it otherwise runs well. I would start by checking/changing the filter. Here is a video where some did one.

Excellent video, that will help a lot. Thank you.

Alldodge- Thank you, I'm going to hope it's the filter, but am going to pick up a gauge today in case it's not. I'll also do the pressure test this weekend. The boat sat outside, uncovered before i bought it. Old owner didn't use it that much or take care of it. It was wet, needed new carpeting ect. It's now stored inside, hopefully there's not water in the gas tank.

 

[WeekendCruise]

I'm actually going to try this tonight. I called my regular mechanic to see what he thought and he said there is no filter on the pump? It looks the same as the pump in pictures/video so i'm thinking there has to be.. He said it's probably the choke... does this make any sense? The choke did get replaced & adjusted because it wasn't opening when warm earlier this season, but i'm not sure how waves/turn could effect it. I'm bringing my normal tools/socket set. If any one happens to see this is there anything else required for the fuel filter changes? Thanks.

 

[pmill]

I just did a carburetor rebuild on a Mercarb and instructions point out that if the spring loaded needle is used on the carb you may experience hesitation or stalling on sharp turns. I don't have anything else to add technically, just wanted to point out this known issue in case it helps.

 

[WeekendCruise]

OK- got some work done today & took some pictures/video...

First thing i did was disconnect the fuel line from the fuel pump... i blew through the line back in to the tank... air came out of the vent for a second.. then gas/water.. My girlfriend said it smelled like gas, but not as strong as it should have... if that makes sense. Is this normal? I would think only air should come out.

Second thing was seeing if fuel was draining down the return line from the carb back to the pump... as far as i could tell it was not. I disconnected it from the pump.. and the hole going in to the pump seemed to be clogged with "gunk" or dirt. Cleaned it out a little but hard to do.

Third- Was checking all connections, lines & for a water separator. Everything looked good and it does NOT have a water separator currently installed.

Fourth- Removed the fuel filter from the bottom of the pump. It was kind of brittle and was not easy to blow air through. Not sure what it SHOULD look like, but see the pic below. I followed All Dodge's advice and poured the contents in to a dish.. there is a LOT of particles floating around.. maybe a little water but not sure. See pic below.

I started it up and ran it a few mins before all this and it all sounded ok. The gas line and vent line are hard to get at where they attach to the tank. If someone can tell me if the filter looks bad i'll replace it, heck i'll just replace it either way since it's off.

Any ideas/suggestions from all that?

Also- Notice the picture of the drive oil... it looks white/tan on the bottom.. I asked my mechanic about this earlier in the season and he said not to worry.. it's because he used a light colored fluid and it mixed a little with the green from before.. Make sense? I feel like if it was watery it would be on top..

Thanks in advance.

In the bottom picture notice the screw that is loose behind the fuel pump.. should this be tightened or is this something that SHOULD be loose?

 

[WeekendCruise]

 

[WeekendCruise]

 

[Cptkid570]

Are you sure it isn't a loose wire to the coil or something? Just seems like when the boat giggles, it stalls.

Anyway, if you are truly concerned about whether or not it is getting gas, install a clear, in-line fuel filter. A perfect spot would be between the valve cover and the carb. You have that long, straight fuel line there.

http://www.iboats.com/Moeller-Clear...1994624--session_id.050651394--view_id.391050

For something that is $10, it will give you an instant diagnostic as to whether or not the carb is getting fuel.

 

[funk6294]

From the pix that filter looks pretty nasty. If I had to guess based soley on where it was located it has probably never been changed. Also I couldn't tell from the pic of the gas in the bottle, but did it have water it? The bowl/filter set up that is on there should work to seperate the water as well as filter the fuel. All a seperator does is provide a bowl at the bottom for the water to collect. As cptkid noted you could put a clear filter in line if you think it's choking off fuel. I will caution you however I would NOT use that particular filter or the automotive version of it either for anything more than a single test run. I have used that style filter before and have had the body start to loosen and leak, it just not a good a design. (Sorry if I seem overly passionate about the moeller filter I am still having flashbacks to the huge gas puddle/fire hazard it created) Last but not least, I am a little suspect on your mechanics drive oil explanation. While he maybe correct that he added a different color fluid I would press him about specifically what oil he added. The merc High performance gear lube (green/blue in color) should not be mixed with the standard (premium as labeled by quicksilver, amber in color) gear lube.

 

[alldodge]

OK- got some work done today & took some pictures/video...

First thing i did was disconnect the fuel line from the fuel pump... i blew through the line back in to the tank... air came out of the vent for a second.. then gas/water.. My girlfriend said it smelled like gas, but not as strong as it should have... if that makes sense. Is this normal? I would think only air should come out.

Could be OK, the vent line in most cases has an up loop in it. This loop can have some condensate in it.

Second thing was seeing if fuel was draining down the return line from the carb back to the pump... as far as i could tell it was not. I disconnected it from the pump.. and the hole going in to the pump seemed to be clogged with "gunk" or dirt. Cleaned it out a little but hard to do.

Third- Was checking all connections, lines & for a water separator. Everything looked good and it does NOT have a water separator currently installed.

The sort of clear line is used to push gas to the carb if the diaphragm in the fuel pump ruptures. It never has anything in it except gunk unless the pump goes bad.

Fourth- Removed the fuel filter from the bottom of the pump. It was kind of brittle and was not easy to blow air through. Not sure what it SHOULD look like, but see the pic below. I followed All Dodge's advice and poured the contents in to a dish.. there is a LOT of particles floating around.. maybe a little water but not sure. See pic below.

Agree with others that needs to be replaced. There is also a filter screen in the carb under the large nut which the fuel line connects to. This to needs cleaned or replaced.

I started it up and ran it a few mins before all this and it all sounded ok. The gas line and vent line are hard to get at where they attach to the tank. If someone can tell me if the filter looks bad i'll replace it, heck i'll just replace it either way since it's off.

Any ideas/suggestions from all that?

I still think you have a fuel issue, and from the looks of the filter your carb is probably pretty dirty. All the bumping and or turning may just be stiring things up of causing the needle seat to move. Either way a good cleaning and rebuild would be in order as I see it.

Also- Notice the picture of the drive oil... it looks white/tan on the bottom.. I asked my mechanic about this earlier in the season and he said not to worry.. it's because he used a light colored fluid and it mixed a little with the green from before.. Make sense? I feel like if it was watery it would be on top..

The change in color of the bottle should not happen just because a different color lube was poured in. If this is the case then the lube used is not compatible with what is in the drive and can cause damage. I would take the bottle off and clean it out real good with diesel. The discoloration could also be from build up in the bottom and it more like sludge. The bottles can get this way over time if not clean out ever so many years.

In the bottom picture notice the screw that is loose behind the fuel pump.. should this be tightened or is this something that SHOULD be loose?

I think this use to have a clamp on it that held the fuel line right next to it.

 

[Zookeeper 2280]

I may have missed it, but I didn't see any mention of checking the anti-siphon valve on the gas tank. I had a similar fuel starvation issue earlier this year and found some crud plugging the anti-siphon valve that was restricting the fuel flow. After I cleaned it out the boat ran great, i didn't even have to replace the valve. If you're seeing debris in the filter, there's a good chance you have some larger pieces stuck in the valve.

 

[WeekendCruise]

Ok.. wanted to report back.

Successfully changed the filter at the fuel pump with no problems. Checked for leaks while using the muffs in the driveway- no leaks and was running good.

Changed the lower unit oil... guess i was being paranoid.. it seemed OK and wasn't milky.. did not seem like there was any water present.

Took the boat out.. same problem.. started cutting out at high RPM but got worse.. the time we made it back to the dock i could only go idle speed. Forgot about the other filter by the carb so i decided to check it at the dock. Found & removed the filter, it was pretty dirty/black... didn't have a spare on me but tried the boat out without the filter in it for a few minutes.. it ran like a new boat.. My rpms's were 200 higher(ish) and we were going 38 WOT instead of 32/33.. I could not believe that small filter was causing such a problem..

Next step is to try it with a new filter put in.. I figure it either has to be the filter or the fuel pump. Maybe with the filter gone the fuel pump is meeting less resistance so it's running better. It's either that or the filter was so clogged gas wasn't getter by.

New problem- After starting i always check the bilge. This time out of no where water was leaking in around the bottom of the housing where it bolts on to the transom. Possible it was running from somewhere.. Only when the engine is running.. a small trickle/stream.. almost in spurts.. not constant. It's under the drive train, at the bottom of everything, near some black hoses. Boat was not over heating. The boat has brand new bellows so i can't image where this water is coming from & hoping it won't be an expensive fix. It was not doing this the last few times.

Thanks all.

 

[alldodge]

Ok.. wanted to report back.

Successfully changed the filter at the fuel pump with no problems. Checked for leaks while using the muffs in the driveway- no leaks and was running good.

Changed the lower unit oil... guess i was being paranoid.. it seemed OK and wasn't milky.. did not seem like there was any water present.

Took the boat out.. same problem.. started cutting out at high RPM but got worse.. the time we made it back to the dock i could only go idle speed. Forgot about the other filter by the carb so i decided to check it at the dock. Found & removed the filter, it was pretty dirty/black... didn't have a spare on me but tried the boat out without the filter in it for a few minutes.. it ran like a new boat.. My rpms's were 200 higher(ish) and we were going 38 WOT instead of 32/33.. I could not believe that small filter was causing such a problem..

Next step is to try it with a new filter put in.. I figure it either has to be the filter or the fuel pump. Maybe with the filter gone the fuel pump is meeting less resistance so it's running better. It's either that or the filter was so clogged gas wasn't getter by.

New problem- After starting i always check the bilge. This time out of no where water was leaking in around the bottom of the housing where it bolts on to the transom. Possible it was running from somewhere.. Only when the engine is running.. a small trickle/stream.. almost in spurts.. not constant. It's under the drive train, at the bottom of everything, near some black hoses. Boat was not over heating. The boat has brand new bellows so i can't image where this water is coming from & hoping it won't be an expensive fix. It was not doing this the last few times.

Thanks all.

As I see it you found your problem. A dirty filter will not pass fuel at a high rate (higher speeds and WOT), should just need replacing.

As for the water leak, since it only leaks when it's running, check the hose and connections coming from the drive. When the engine is running the water pump has increased pressure on the line