Engine Hesitation at full RPMs, plus a small leak?
Summerrental
Member Posts: 35 ✭✭
I seem to be having a problem with the engine only when revved at full RPMs trying to plane off. The boat idles fine there doesn't seem to be any issues
until I increase the RPMs. When I do this I get hesitation and it doesn't go to
full power immediately. If I stay at it it will eventually get to full speed
but not without fluctuating up and down on the RPMs, but even then is a rough ride. So to inspect further, I opened the engine
compartment while I was running to take a look and I did also hear a clunking
sound once in a while,.. not really sure what is causing that. When I got back to dock I took a closer look in the engine compartment and I noticed
a very small spraying of water coming from the bottom of the serpentine belt. I can't
seem to locate where the water is coming from but it's a very small amount It seems to be wetting the belt and the belt in turn will spray a fine mist around the engine
compartment. So it seems I have a leak somewhere while the boat is
running but it's not evident where it's coming from at this point.
Some background on the boat: It's a 2005 270 Fiesta Vee, with a 350 Mag MPI engine, and it's well maintained every year by me. I change the engine oil, oil filter, fuel water separator, and gear lube every year. I also inject grease into the gimbal through the exterior port on the stern drive every year. 2 years ago I had the drive removed, the gimbel was inspected and the shift bellows was replaced along with the shift cable; The gimbal was in Factory perfect condition when it was inspected. The one thing I have not done yet, that is overdue is my manifold and risers which I was planning on doing this year. My water flow from the raw sea water pump/ impeller seems very good. I replaced it about 6 to 7 years ago and I haven't had any temperature issues or water suction problems. When I replaced the water impeller I noticed it was very heavy duty unlike the small ones you see in generators so I assumed this would last for many seasons as long as I did not pull up anything from the bay.
Again, at idle the engine runs perfectly, it's only when the engine is revved to full power.
On a side note I did have a similar issue 3 years ago and I had a Rinker dealer look at it. It turned out it was a problem with this engines computer. Apparently there is a safety check built into the engine that prevents the engine to rev over 4000 RPMs when the boat is in neutral. The problem I was having was the engines computer was telling the boat that the engine was a neutral all the time,... even when it was in forward gear. Thus this was preventing me to achieve full RPMs when going in full forward power. The dealer correct the situation in the engines computer and I didn't have a problem since. I'm not going to rule out this as a potential problem again and I will have them check it, however I didn't have that slight leak that I mentioned before the last time this happened so I'm wondering if there's a different problem at hand. Any ideas?
Thanks for any input guys! Not a great start to the boating season.
Comments
Is this the first time you have had the boat out this season?
If it is, did you have the boat winterized? If you winterized your block did it get done properly? I don't think you have a cracked water jacket but I've seen weirder things with boats.
I assume your engine is raw water and not coolant/heat exchanger cooled. The water spraying could be a lot of things, some no big deal and might not be connected to your engine's erratic acceleration.
I'd try to find the origin of it. Small things first: I'd check and engine block winterizing water draining ports to ensure they are tight (these are blue on newer models), then hose clamps on any cooling hoses.
Do you have a B3 drive? !s your water pump in the outdrive or a sea water pump that is belt driven? If you have a belt driven sea water pump is it leaking?
I would have said look at your risers but if the water is definitely coming from low down on the engine it probably isn't connected to them.
Any information as to the definite location will help us diagnose your condition.
As for the erratic acceleration I would want to rule out the potential that your engine guardian system has again malfunctioned. You didn't say that your engine was overheating so I assume your water loss was not enough to set off a low water pressure alarm and put the engine guardian into reduced engine power mode.
So, engine acceleration: engine guardian? IAC? Fuel filter? Spark plug/wire/cap, fuel injector jet?.....
I think you have two separate things going on and have to deal with each one independently.
lets see what the other guys come up with?! Good Luck!
Well, I think MT basically covered the items I would say. Most importantly, I also believe you have two separate things. You should be able to easily follow the water leak. I'm betting it's coming from the sea water pump (bottom pulley on stbd side).
As far as replacing the impeller, that really should be done every 2 years. I've seen many of them not last past a 3rd season.
As far as the power, not sure it sounds like guardian. To me it could be coil. Although the clunk noise may indicate something else.
Dream 'Inn III -- 2008 400 Express
Thanks a lot for the quick comments guys!
I have been winterizing the engine block with antifreeze every year using an external 5 gallon winterizing kit. I run the engine on hose water for about 20 minutes, and once it is a the highest temp I can get it to, I open a valve and drain the 5 gals through the engine block. I typically see the pink antifreeze coming out the exhaust ports of the Bravo 3, then I fog the engine with fogging oil. Once that’s complete I unscrew a few of the blue drain plugs to ensure the antifreeze made it past the thermostat. Sometimes the water is so cold it doesn't open even after running the engine for 20 mins. (Running at idle in the cold weather doesn't always heat up the temp enough)
I will check the blue drain plugs because they are in need of replacement anyway. They are all getting brittle and the wings on the one by the water pump housing snapped off on me last season when I was trying to drain the block. I bought new ones on Amazon, but I have not yet installed them. I will check that first.
This is the first time I took the boat out this season, I don't have any temperature issues, the temp indicator is always at the perfect spot. The water leak is literally a mist, and almost not detectable until it builds up a bit and starts getting on the belt. Then the belt send small splashes flying around.
I do have a belt driven raw sea water pump that is run by the serpentine belt (not antifreeze with heat exchange). It does seem to be leaking in the vicinity of the water pump housing, but it's very difficult to tell. I don't like to get too close in the cramped engine compartment while it's running. It’s especially difficult to see what is going on under the engine while it is running. It’s so cramped in there I need to use cameras and mirrors to see anything.
I also want to add a new issue. I went back down to the boat today to be sure there is no excessive water leak, and as soon as I opened the camper canvas I smelled gasoline. I don't think this can get any worse! L I turned on the blower and opened up the canvas and I did not start the engine. I inspected the engine compartment and I did not see any leaking gasoline in the bilge, but the compartment did reak of gasoline. The only thing to note is that I filled the tank just before I launched it. I filled my 100 gallon thank with 92 gallons. I will keep looking and seeing if I can find any more info. (…and yes I used Startron ethanol treatment for the new gasoline)
First about the fuel. I suspect (and hope) that the cold fuel from the supply tank has expanded in your own boat's fuel tank, overflowed out of the vent (not supposed to but it does) and it only takes a very little to drip onto the gelcoat under the vent then the wind blows that smell everywhere. Fingers crossed.
About that spray. When looking for a bugger of a leak one time on my boat an old salt told me to get a good light with a narrow beam (today one of those small pencil leds would do it). he was right I ran the engine and shone the narrow beam around the suspect area. As the engine heated up there was a constant drip of water from a hose that I was sure was good. It was easy to spot at night and with the flashlight I didn't have to worry about getting my hair (when I had a lot waaay back) in the belts.
Yes, ignition coil.
Good Luck.
Secondly, I want to change the in line fuel filter shown in the pictures in the post above. I cant seem to figure out where to get this. I've seen pother posts that have a fuel filter ion the engine itself, but not this one. (It looks like a little juice can) Is there another fuel filter that I am not aware of? or is this it? (I know about the fuel/water separator, and I replaced this)
Thanks again!
In-line fuel filter #'s
Mercruiser - 35-864572
Sierra - 18-7721