Rough idle indmar assault efi

[Meyeronfire]

Ok here's my first issue with my 03 launch ssv. Running the indmar assault fuel injected motor. Took it out yesterday for a short ride to a sandbar about 10 mins ran normal there and back. Today out ran fine for about 15 mins and decided to start running rough while in idle and also running a bit rough while going 2600rpm. I let it run for a bit longer and seemed to run a bit better but still idling rough. Even killed the motor a few times like its not getting any fuel. My first thought would be a filter issue but wanted to check here first before running around town gather parts. I bought the boat in mid July this year and everything has been great have put almost 60 hours on boat with no issues until now. I bought the boat from a dealer here in houston and they supposedly checked everything and did a service on it before I took it home. I did however change the oil and filter about 10 hours ago did it myself. Any ideas where to start would be appreciated!

Thanks Matt

[Meyeronfire]

Anyone have any input?

[Meyeronfire]

Also run primarily in saltwater, dont know if that makes any difference.

[SquamInboards]

Sounds like there might be some water in the fuel, I would check / change the fuel filter and look for evidence of water in the fuel. More than likely you could pour the contents of your filter into a clear glass jar and let it settle for a few hours to see if any water appears at the bottom. I don't know what the filter setup is on that engine, but I'm sure someone here does. That's where I would start.

[MJHKnox]

1) Fuel Filters are a good start. Try SeaFoam gas stabilizer. Then some high octane gas.
2) Cap and Plugs replacement if it has not been done recently. Inspect the wires, they last a long time.

Mark

[Meyeronfire]

Thanks for the replies guys. Going to try these suggestions. Does anyone now a part number for the fuel filter? And is it ok to put day oil filters and fuel filters that you get from auto parts stores ok to use in the boat?

[MJHKnox]

I have the 325 motor in my 2007 SSV. Per a buddy that works on these boats, (workeed at the Supra Dealer) he buys from the auto parts store. Mine was Federated - Hastings GF333. It replaces the Fram PGF333 or WIX33299.

I would call the dealer with your motor number and ask them for the part number. Then you can cross-reference.

I do not think the part number is on the filter. So it probably will not help you to take the old filter out.

They are easy to change out. He recommended to me to change it out when I change the oil - 2x year. He claims it's cheap insurance.

Mark

[Meyeronfire]

I have the 325 motor in my 2007 SSV. Per a buddy that works on these boats, (workeed at the Supra Dealer) he buys from the auto parts store. Mine was Federated - Hastings GF333. It replaces the Fram PGF333 or WIX33299.

I would call the dealer with your motor number and ask them for the part number. Then you can cross-reference.

I do not think the part number is on the filter. So it probably will not help you to take the old filter out.

They are easy to change out. He recommended to me to change it out when I change the oil - 2x year. He claims it's cheap insurance.


Mark

Thanks alot man, I'm really hoping this isnt a huge issue, this is my first boat I have ever owned and im losing sleep over this thing!

[Meyeronfire]

Ok guys a little update on the boat. I'm 95% sure there is a little moisture in the fuel. Changed the fuel filter and poured the fuel that was in the filter Into a glass jar, also before changing the filter I poured 1 1/2 cans of seafoam in the tank and filled with premium fuel. I did not see signs of any major water /fuel separation so I'm hoping there is just a slight amount of moisture. After replacing the fuel filter boat started right up and I ran it on the hose for about 20 mins... Took it to the water for a water test ran it for about an hour. Ran it at idle speeds low rpms and wot ran just like it supposed to however on the way back in it decided to start idling rough and sputtering again... I think it may be working the water out of the system??? Think I may empty the new fuel filter and Corday some carb cleaner to dry anything up. Am I on the right track guys???


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[Meyeronfire]

Little update on the situation. Extremely frustrated at this point and probably going to just take it in. Filled tank with premium fuel and added a can and half of seafoam, Replaced fuel/water seperator with a slightly larger size, correct diameter just a bit longer dont think it matters just holds a bit more fuel. Took the boat for an hour to test after replacing, started up fine ran great and thinking its back to its normal self. So on the way back in it started idling rough and doing to same thing it did the first time it started with the problem. I didnt have the time to take it back home and try to mess with so it set for a week and the following I was back pulling the fuel filter off and cleaned and replaced, the boat had quite a bit of trouble starting. So I pulled the plugs to inspect and didnt really like what I found 6/8 plugs seemed like they where dry, not even a slight amount of oil on them??? even the bottom of the threads seemed like they where just slighlt melted. And not the electrode or anything like that is melted is just on the base of the spark plug where they first begin to thread. I dont know how to post a pic. I thought maybe the exhaust manifolds could be clogged with something? Is that even possible? Anybody have any last suggestions before I admit defeat and just haul the thing in?

[CornRickey]

Well, given you situation were you don't have the ability to work on it then try it out except for the weekends it might be time to take it in. Your plugs shouldn't have any oil on them but I think you are thinking in the right direction. It sounds like heat soak related and not fuel now which usually means ignition/electronic (remembering that your fuel pump is electric). If it was mine and I was going to continue to work on it I'd inspect the cap/rotor/wires then replace, replace the plugs (your description doesn't make sense to me without pictures) then I'd check out the main harness connection under the main breaker making sure the contacts are good (mine went bad) then the computer contacts. When it starts running cruddy does it smoke and smell like fuel. You may try pulling plug wires when it does to see if it doesn't change. Also I wouldn't rule out fuel pressure.

[Meyeronfire]

Well, given you situation were you don't have the ability to work on it then try it out except for the weekends it might be time to take it in. Your plugs shouldn't have any oil on them but I think you are thinking in the right direction. It sounds like heat soak related and not fuel now which usually means ignition/electronic (remembering that your fuel pump is electric). If it was mine and I was going to continue to work on it I'd inspect the cap/rotor/wires then replace, replace the plugs (your description doesn't make sense to me without pictures) then I'd check out the main harness connection under the main breaker making sure the contacts are good (mine went bad) then the computer contacts. When it starts running cruddy does it smoke and smell like fuel. You may try pulling plug wires when it does to see if it doesn't change. Also I wouldn't rule out fuel pressure.

The last time I was out and it started to run cruddy on the way back in I didnt smell any gas or notice any smoke...the following week, I pulled the plugs went to the auto parts store and replaced with ones that crossmatched the old plugs, I dont think the new plugs are stainless which I will replace pretty soon since I run primarily in salt and brackish water. When I replaced with the new plugs boat seemed to run normal but I decided to turn the boat off and see how it would start back up when I was out and heres the weird thing, Tried to start the boat back up and when I turned the key... its like it was dead, althought the gauges would turn on, boat woulding even attempt to start! I dont understand!

[CornRickey]

ok, take off the battery cables and check for not only corrosion on the terminals but at the starter and on the block. Also check the cables themselves for corrosion inside the insulation and for them to be stiff. also check the main wire harness plug under the 40 amp breaker. It sounds more and more like electrical. You probably bumped something when you changed the plugs and that fixed the problem momentarily.

[Meyeronfire]

ok, take off the battery cables and check for not only corrosion on the terminals but at the starter and on the block. Also check the cables themselves for corrosion inside the insulation and for them to be stiff. also check the main wire harness plug under the 40 amp breaker. It sounds more and more like electrical. You probably bumped something when you changed the plugs and that fixed the problem momentarily.

Hey man, was wondering if you had any problems like this or heard of any others since you own the 03 same as mine? And I think I will give it one more shot, check all wiring and clean if necessary and check rotor a distrib cap for corrosion, I don run in saltwater sometimes, is that hard on the exhaust manifolds?

[Meyeronfire]

Anybody have any other suggestions?

[CornRickey]

My cousins Master craft did this. He cruised up to the dock from the other end of the lake with no problems. it wouldn't start after sitting there for a couple minutes. we found the positive cable with corrosion within the cable and it was crackly whe. you bent it. I changed the gauges in my Supra and the temp gauge was bouncing all over the place. Finally found the main harness plug under the breaker had some bad contacts and the fuel gauge was one of them. If I wiggleditenough the engine would start running bad.

[Meyeronfire]

My cousins Master craft did this. He cruised up to the dock from the other end of the lake with no problems. it wouldn't start after sitting there for a couple minutes. we found the positive cable with corrosion within the cable and it was crackly whe. you bent it. I changed the gauges in my Supra and the temp gauge was bouncing all over the place. Finally found the main harness plug under the breaker had some bad contacts and the fuel gauge was one of them. If I wiggleditenough the engine would start running bad.

Is the main harness under the dash?

[CornRickey]

the connector I'm talking about is mounted under the 40amp breaker in the engine compartment

[Meyeronfire]

Does anyone think I could possibly have a bad fuel pump? I called my dealership and he recommended that I start there considering they have changed a dozen fuel pumps this season and they only work on supra and moomba.

[jzelt]

Buy a fuel pressure gauge at the auto parts store. There should be a plug on the fuel rail. That should rule on whether fuel related or not. Mine being a throttle body injection, reading is around 32 psi. I believe direct injection is 60 psi. (Chevy suburban 1999 5.7 or corvette usually have similar auto parts, ie the idle air control valve, throttle position sensor, etc). I had to replace our fuel pump last year, but it just died and wouldn't work. (even powered directly).

[Meyeronfire]

Also going to check coils. Do you guys have a good and easy method for this?


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[CornRickey]

a bad fuel pump would not cause a bad battery/ no start issue. You need to find that issue then move onto you original post problem that could be a fuel pump. easy and obvious first.

[Meyeronfire]

a bad fuel pump would not cause a bad battery/ no start issue. You need to find that issue then move onto you original post problem that could be a fuel pump. easy and obvious first.

UPDATE, Took the boat in, had quite a few error codes. The main issue was a low bat/ low voltage error that caused the electrical system to go haywire, making the fuel system flood the throttle bottles this being an issue and having a hard time to start after it would start acting up after 45 mins- hour. Also an overheating code too, which maybe it was going into limp home mode? Anyway the mechanic said he was out for about 2 1/2 hours and the boat ran perfect. So i suppose we will see next season how everything works I/m having it winterized and putting it up for the winter. So what are some things I can do to prevent these error codes? And I really hopes this help someone else having issues with their boat.

[Meyeronfire]

THE ISSUE REMAINS: Ran on hose for 1 hour ran fine. took to the water started acting up after about 1 1/2 hours. Starts to run rough while idling but does not seem as bad as last season. When the mechanic had it he cleared all the error codes stating that was the culprit... explanations in previous post. The only thing that seems different to me is it sounds like the fuel pump is sucking air??? I replaced the fuel pump last season so I know its fine. Also for some reason this issue seems to start 45-1hour while the boat is under a load and then when I get home to fire it up and flush it, it has a hard time restarting but always starts back up. I can always seem to restart the motor.... ANY IDEAS GUYS?? Thank you for reading all of this and thank you all for trying to help. I just can't stand throwing money at mechanics who don't fix the issue. Just want to plug it in to a computer and tell them whats wrong so they have a quick fix.

[BGeorge01]

I would like to see what people have as a response to this cause I to have this issue from now and then. Runs great for about a hour or so then when it's at idle it starts sputtering and almost dies. Sorry I don't have a solution but maybe someone does.


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[CJD]

You wrote that your mechanic cleared the codes. Did he actually fix any of the causes?

Also, whenever I have an engine that runs great cool, but acts rough when hot, my first thought is ignition coil. It is very common for coils to work when cool. But misfire when hot.

[Zim]

Did you ever find any debris in the fuel when you dumped out the filters? The tank could be dirty inside, and after running for a bit the debris that was settled at the bottom of the tank gets shifted around and sucked into the fuel system. Also, how is the condition of your fuel lines? Those start breaking down over time and you may be having an issue with a fuel line collapsing while under pressure.

Do you have the ability to check the timing? That can cause issues too.

Are all of your plugs gapped correctly?

Just a couple more suggestions to check out.

[Meyeronfire]

You wrote that your mechanic cleared the codes. Did he actually fix any of the causes?

Also, whenever I have an engine that runs great cool, but acts rough when hot, my first thought is ignition coil. It is very common for coils to work when cool. But misfire when hot.

Yeah thats exactly what I asked when he "cleared the error codes", he states that I needed to keep a hot battery at all times, which I've done. So in all actually he didn't fix squat.

Zim,
A buddy and I worked on the boat for a couple of hours the other night here is what we did and found.

1. Checked fuel pump for leaks, Inspected fuel rail and flow, took an air hose and blew out the fuel pickup line from fuel tank to fuel pump, line is fine the line is not brittle or soft. all flowing normal, we didn't have a fuel pressure gauge. Cleaned fuel filter, didn't find any debris.

2. Inspected fuel injectors, both working spraying evenly in throttle bodies, we did remove inspect and cleaned anyway. Didn't find any trash or debris in filter screens. Diaphragm was fine to. Replaced and ran boat on hose, now when we did this the flame arrestor was off and we noticed that when it starting running bad there was a white residue inside the throttle bodies we are thinking moisture???

3. Then we decided to inspect the tank, pulled some gas from the bottom and put in a water bottle, we noticed small bubbles floating to the bottom of the water bottle and ALOT of fine brown debris, the small bubbles floating to the bottom we think are moisture and small amounts of water am I on the right track guys??

4. Completely drained fuel tank at this point, and there was quite a bit of moisture under the floorboards when we pulled them up and inside the hull. Pulled the tank out dumped the rest of the contents in a bucket and wow, guys there was large pieces of plastic, brown debris, dirt grit and some other stuff I have no idea what it was!

5. Tank is out and completely empty drying in the sun. Putting it back together tomorrow and filling with some fresh fuel, new fuel filter and see if that resolves the issue.

And Zem, as far as coils go, the mechanic supposedly inspected and stated they were normal and also distributer cap and rotor. And also put 8 brand new spark plugs, I'm assuming they are gapped correctly but i suppose I will check, Kind of losing confidence in the mechanic at this point. They just want quick money and to move the next boat in.

[Zim]

If you still have problems when you get it back together, it might be time to find an Indmar tech to diagnose the problem. Could be a problem with the ECM...

[CornRickey]

The bubbles floating in the fuel is water. I think your on the right track with your fuel system. Don't discount plugged fuel lines even if you can blow air through them. Fuel and air are completely different ball games.did it have a screen on the end of the fuel line in the tank?

[chris young]

Just catching up on this thread now. I don't know your motor, mine is the old carbed 351, but I had similar issues with my Volvo (car) this winter and it turned out to be the fuel pump.

I just wanted to add this in for anyone else trying to troubleshoot similar problems, if you don't have a fuel pressure gauge, (I do but it's at the cottage with the boat) you can use a tire pressure gauge. It works like a charm.

I don't know if your motor will have one, but look for a schrader valve on the fuel rail. If you use the dial type tire gauge you can watch your fuel pressure, if you're using the stick type you'll need to keep a finger putting pressure on it to watch it if it's moving.

[Meyeronfire]

The bubbles floating in the fuel is water. I think your on the right track with your fuel system. Don't discount plugged fuel lines even if you can blow air through them. Fuel and air are completely different ball games.did it have a screen on the end of the fuel line in the tank?

Yup sure did, when I peaked inside the tank it looked as if it was plugged up as well so we cleared it out.

But FINALLY, the issue seems to have been resolved. Put everything back together put a little fresh premium fuel in, and man she fired right up as if she has been running all day! I ran her on the hose for about a half hour, went to the water an ran it for about and hour and half, not a sputter didnt miss a beat, idleing smooth and power is amazing. I feel pretty confident that we have resolved the issue. When I got back from the water from testing, ran on the hose again and looked in the throttle bodies and I did not see any white residue so not only do I think there was a ton of trash blocking the pickup line but the moisture wasnt helping the situation either. Still strange that it would act up after about half hour or so, I'm guessing that everything would get mixed up in the fuel tank? And also my fuel pump sounds COMPLETELY different, I dont know if that makes sense to you guys but seems to be a constant flow and im not hearing any air like I did previously. THANK YOU FOR ALL OF YOUR HELP FOR THE PEOPLE WHO RESPONDED TO THIS. I hope other people will read this and do the same thing.

Questions.

Anything I can do to prevent moisture buildup in the tank?
How often do you guys change your fuel filter?
When should I replace the gas lines?
And how the heck did all that trash get in the fuel tank????

[Zim]

Yup sure did, when I peaked inside the tank it looked as if it was plugged up as well so we cleared it out.

But FINALLY, the issue seems to have been resolved. Put everything back together put a little fresh premium fuel in, and man she fired right up as if she has been running all day! I ran her on the hose for about a half hour, went to the water an ran it for about and hour and half, not a sputter didnt miss a beat, idleing smooth and power is amazing. I feel pretty confident that we have resolved the issue. When I got back from the water from testing, ran on the hose again and looked in the throttle bodies and I did not see any white residue so not only do I think there was a ton of trash blocking the pickup line but the moisture wasnt helping the situation either. Still strange that it would act up after about half hour or so, I'm guessing that everything would get mixed up in the fuel tank? And also my fuel pump sounds COMPLETELY different, I dont know if that makes sense to you guys but seems to be a constant flow and im not hearing any air like I did previously. THANK YOU FOR ALL OF YOUR HELP FOR THE PEOPLE WHO RESPONDED TO THIS. I hope other people will read this and do the same thing.

Questions.

Anything I can do to prevent moisture buildup in the tank?
How often do you guys change your fuel filter?
When should I replace the gas lines?
And how the heck did all that trash get in the fuel tank????

Glad to hear things are working normally again. Fuel is inherently dirty, which is why there are fuel pumps in the first place. Marine grade fuel is a little better (stuff you usually find at marinas) but you still need to keep an eye on things.

Dirt can come from many places. Opening the tank to fill it, over time dust and debris will get in there. Water/condensation can also be very dirty and the remainder of the water in the fuel will leave dirt deposits. Plus the fuel lines lots of times will rot away from the inside, which backwashes into the tank and leaves lots of dirt/debris. I'd still recommend replacing your fuel line if you haven't already.

As for preventing future moisture, use some fuel stabilizer if your boat will be sitting for any extended amount of time (more than a couple weeks). Do this especially if you're in a humid or very hot climate.

Now... time to enjoy the summer :)

[CornRickey]

It's my opinion marine fuel had more potential to be fouled due to seasonal use and lower stock turn over. Add the fact that a significant amount of boats are refueled from gas cans and the boats sit over winter, you have allot of potential of foreign bodies.