Tweet
Towards the end of last season I started having problems with the engine sputtering at higher rpms. I replaced both fuel filters and the problem went away. After sitting for 3 months I took it out and it ran great going out to a cove where I sat for awhile. But when I started it up to head back in it idled rough. Still ran good at 1500 rpm and up. The next week I went out again and it wouldn't even start unless I gave it some throttle. Once out it ran terrible. Sputtering very badly as if it was getting way too much fuel. But no smoke or smell of raw fuel. I had put fresh fuel in the tank with a quality stabilizer prior to letting it sit those 3 months. I am going to try running it on a remote fuel tank to make sure fuel is not the problem. Also the ECM is not showing any codes. Any help would greatly appreciated.
-
-
Next time it's running rough, take the engine cowl off and see if it improves.
If it does, then check the port side of the engine holder just below the fresh water flushing connector (near the trim switch), you probably have to take the lower engine cowlings off to see it. Look for corrosion holes in the steel plug in the engine holder just there, it burns a hole thru to the exhaust. Caused by steel plug in ally engine holder.
Unfortunately it's a well known problem in the DF90-140 series engines prior to 2009. Do an advanced search on this site for "Suzuki engine holder corrosion" and you will find plenty of info on the options you can do to fix it.
A visual check as described above will quickly reveal if this is the problem or not. -
As I was reading his post, I was thinking the same exact thing. Good call.Originally posted by Moonlighter View Post
-ShawnComment
-
Appreciate the response. However I ran it today on a remote fuel tank and with cowling off and no change. It was a bit warmer today than the two previous days and it did start without any throttle and idled even with cowling on. But still running rough. When idling the entire boat shakes. Still no codes from ECM. Put some Seafoam into fuel tank and ran for awhile. Will let it sit overnight and try again tomorrow. Any other ideas of where to look next?? ThanksComment
-
If it's shaking that bad at idle and running so poorly, I would suspect one or more cylinders are having a problem of (1) dirty fuel injector, (2) fouled or worn spark plug, or (3) you have water in the fuel (phase separation in ethanol-laced fuel. No amount of stabilizer will prevent phase separation).
Most other causes (such as failed MAP sensor) would throw a code.Mike
μολὼν λαβέComment
-
What about a dirty iac valve? Bad plug, coil, or maybe blocked HP filter? Does it run better at higher speeds?
Just thoughts, good luck.Comment
-
I ruled out fuel as the problem when I tried a remote tank. Plus I only use ethanol free gas anyway. When the problem first started it would run fine at higher rpms. But it now runs rough through the entire rpm range. As I stated in the original post the problem started rather suddenly and continued to get worse each time I run it. I just changed both fuel filters a few months ago. I've had issues with the primer bulbs on other boats and am debating getting a new one to see if that changes anything. I just hate to start throwing new parts at it but with no codes I am at a bit of a loss as to what else to do.Comment
-
Well, that's fine. Don't check those things we've suggested. Nobody here has even remotely suggested that you throw new parts at it, but if you're not willing to check those items that we've suggested, throwing parts is exactly what you're going to end up doing. If you don't know how to check your plugs or your injectors or your fuel pump or the IAC or any other part of your motor, then take to a mechanic. And when you get there, tell him to check the valve clearances while he's at it. Truth is, there's any number of things that can cause your symptoms and still not throw a code. You just have to be willing to check them out. But if your not able or willing, then I'm sorry to have wasted your time.Last edited by Harper; 04-01-2015, 04:24 PM.Mike
μολὼν λαβέComment
-
Sorry if I offended you. I love these forums and have had great success with them in the past. I'm not sure why you feel I am ignoring the suggestions. Both fuel filters were replaced. Different fuel and fuel tank were tried. I tried running it with the cowl off as suggested with no change. A bad IAC should not cause a problem at higher rpm, (unless my service manual is wrong). The spark plugs are new. The fuel injector solenoids are working. I am going to check each cylinder tomorrow and see if I can isolate a specific cylinder as the problem and then check the injector and coil. I have owned boats for over 30 years and try to do all the mechanical work myself. Most of the time it is diagnosing the problem that is the hardest part. That's why these forums are so great. Again sorry if you felt I was ignoring the suggestions. But I assure you I give each one consideration.Comment
-
Still suggest you check the steel plug in the engine holder, below where the flushing attachment is located. It's quite a common problem in the earlier year 90-140 series engines. It is worth inspecting it just to be safe that the dreaded engine holder corrosion hasn't started to rear it's ugly head.
Do you run a water separating fuel filter (eg RACOR style) between the tank and engine? Well worth putting one in if you haven't got one already, as the small filters under the cowl really can't cope with a bad batch of fuel and can clog up again almost immediately if that is the case.
Also, as you would be aware, it wouldn't be the first time that a new spark plug was bad, or a plug lead developed a short soon after a new set of plugs have been put in. Probably that will become apparent when you check each cylinder.
I will add one thing that may not seem directly relevant but sure as eggs can be! A frequent cause of running problems with these engines is power supply. Please thoroughly check the batteries, connections and main battery leads to ensure they are clean, tight, and free of corrosion, cables in good condition, and that batteries are charged and pass a load test.
Let us know how you do. And yes, it does help if you do reply, telling us which of the suggested issues have been checked.Comment
-
I wasn't offended, just trying to figure out why you indicated no use for the suggestions. You never indicated that you had done anything other than try a different tank, and certainly nothing about our suggestions.
So anyway.....let's forget all that....I agree that the IAC shouldn't be the cause, since it's a problem at all RPMs. I think solarman missed that you indicated about halfway through your first post that it had become a problem at all RPMs. Have you checked the valve clearance. We've noticed occasional problems in the past of valve clearances so tight that a few valves faces eventually burned, and would no longer seal properly (do a compression check?)
I was also curious in your first post why you thought it acted like it was running too rich rather than too lean. You might consider vacuum leaks, which would mean any of the gaskets at the intake (IAC gasket, throttle body gasket, or manifold gasket), or any hoses involved with the intake system, or possibly a crack in the manifold itself. I would also check for the correct fuel pressure at the fuel injection rail. You might have a weak/failing high pressure fuel pump, or bad pressure regulator (in the VST).
One last revisit to moonlighter's post.....did you visually check for that ferrous plug at the engine holder (even if removing the cowl didn't change anything)?Last edited by Harper; 04-01-2015, 10:44 PM.Mike
μολὼν λαβέComment
-
Yes, I did miss that part about going through all RPMs, it is easy to miss some points on this side of the forum, sorry for that.
Is it possible the MAP sensor could be dirty, getting blocked?
Good luck, let us know what you find.Comment
-
Something else to consider. Just because you ran fresh fuel from an auxiliary tank doesn't necessarily mean you are free and clear from fuel issues. The VST could be dirty/clogged. One or more injectors could be contaminated/clogged.
-ShawnComment
-
First let me say again how much I appreciate all the help I got on this forum. I wanted to report that the problem has been found and corrected. And it was a really easy fix. In checking each cylinder today I noticed what looks like burning on the ceramic portion of the spark plugs where it mates with the metal. Never seen anything like that before. But before going any further I put new plugs in and it now purrs like a kitten. Not sure what caused the burning since the metal portions showed no signs of overheating and the electrodes were a even tan color. I bought this boat a year ago on consignment and among the work the seller paid the marina to complete was new spark plugs. Lesson learned. I feel like a total idiot because I should have checked the plugs sooner. Was just convinced it was a fuel issue in the beginning that I failed to remember the first rule. KISS, and check the basic stuff first. Again thanks for all the responses and I am still going to look at that corrosion issue.Comment
Comment