Engine idle slight vibration & strange noise

[FLJetBoater]

since your in salt water I would strongly suggest adding flush valves to direct all water into the engine,

here is a video of my mr1 without the impeller/pump and you can see how much flush water back flows out of the cooling inlet line that never gets to see the engine,

Yeah you're right - mine is basically doing the same thing. I will look into installing those. That would be the same install as the "tow" valves if you do it in the bilge right? instead of after the Y in the engine compartment?

 

[FLJetBoater]

If you want to do it as a "get to know your boat" exercise and create a known date of maintenance I'm all for it, the stalling at idle could have easily been bad fuel or a bad mix,

I might really suggest you take an extra 30 minutes and pull the pump/impeller/shaft and see what it sounds like, it may be the same but it will be a good learning experience and if you ever have to pull it again you'll be able to do it in 15 min.


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Thanks Scott. I'm going to swap the plugs and see if that changes anything (if for no other reason than just knowing they've been done in the last 6 years) then go from there and remove the shaft.

 

[VitaminSea]

Thanks that's a good tip. So you flush 5 mins first with freshwater, then do you empty the salt away 4oz per engine (seems to take about 7-10 mins) and leave it at that?

I like to target around 7-10mins flushing each engine, but only use the salt-away for the last min or so of the flush. I also do not like to let the mixer empty, as I want some of the salt-away to remain in the cooling passages. I use the balance of the diluted salt away to rinse the bilge, trailer, under carriage of tow vehicle.
I am sure there are numerous approaches to this.

On my list of mods to do is the tow valve install for flushing, as Scott’s video demonstrated a significant amount of water never makes it to the cooling system

 

[FLJetBoater]

Just swapped out the plugs. The old ones are FILTHY. The picture doesn't quite do it justice. Also there's no way these were torqued properly. I BARELY had to put pressure to unseat them. Also not sure if it's because of the rust, but these were all gapped under .030. When I checked the new plugs, out of the box most of them were around .025-.028 or so. I had to open up all of them to between .031/.035

Going to try and get it out tonight for a quick spin and see how it sounds now

 

[buckbuck]

The torque on these plugs is very low. It is common for me to find mine just over finger tight. Hopefully you have isolated your issue. keep us posted.

 

[sunbyrned]

Just swapped out the plugs. The old ones are FILTHY. The picture doesn't quite do it justice. Also there's no way these were torqued properly. I BARELY had to put pressure to unseat them. Also not sure if it's because of the rust, but these were all gapped under .030. When I checked the new plugs, out of the box most of them were around .025-.028 or so. I had to open up all of them to between .031/.035

Going to try and get it out tonight for a quick spin and see how it sounds now


View attachment 126961

Just a thought but are you using the plugs that your manual recommends? The only reason I ask is that for my 242, the gap is usually already within the range for the ones I use.

 

[FLJetBoater]

Just a thought but are you using the plugs that your manual recommends? The only reason I ask is that for my 242, the gap is usually already within the range for the ones I use.

Unless I made a huge mistake I used LFR6A 6668 plugs. They were all under gapped. The manual says .031 to .035. They were all around .027 or so. Maybe I need another gap tool to make sure the one I have is accurate.

it’s a bit better now than it was but there’s still some shake to the engine even when we put it in the water this evening. On Monday I may pull the pump and see how that affects it.

 

[FLJetBoater]

The torque on these plugs is very low. It is common for me to find mine just over finger tight. Hopefully you have isolated your issue. keep us posted.

Tightening those plugs to 18ft lbs seemed to take a lot more effort than what it took me to loosen the ones that were already in there....

 

[FLJetBoater]

If you want to do it as a "get to know your boat" exercise and create a known date of maintenance I'm all for it, the stalling at idle could have easily been bad fuel or a bad mix,

I might really suggest you take an extra 30 minutes and pull the pump/impeller/shaft and see what it sounds like, it may be the same but it will be a good learning experience and if you ever have to pull it again you'll be able to do it in 15 min.


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I'm going to pull the pump this afternoon I think, I have to flush the engines anyway after a couple days in the Gulf water. Anything to be aware of, or look for, or potential issues I could face when I pull them?

 

[WREKS]

@FLJetBoater I would also be checking out the cooling system starting at the water pilot and working toward the oil cooler. I believe the pilot hose comes off the oil cooler. Something is plugged. Did you take in any seaweed, etc. while you were boating?

 

[FLJetBoater]

@FLJetBoater I would also be checking out the cooling system starting at the water pilot and working toward the oil cooler. I believe the pilot hose comes off the oil cooler. Something is plugged. Did you take in any seaweed, etc. while you were boating?

It's definitely possible...the waters around us are fairly shallow there's always a couple weeds in the intake grates but nothing major. There's no overheating issues but you think it could still be plugged? Could I just snake all the way from the oil cooler back to the intakes instead of taking it apart in pieces?
I also noticed the hoses and clamps coming from the intake to the Y don't look to be in great shape so I'll probably replace them when I put in the tow valves.

 

[WREKS]

To start with I would disconnect hose clamp 22 at top of oil cooler and see if air or water can go through the hose. That is the hose for the water pilot. If it is open, the next thing that can be blocked is the oil cooler itself or the cooling water intake. First check the pilot hose.

 

[FLJetBoater]

To start with I would disconnect hose clamp 22 at top of oil cooler and see if air or water can go through the hose. That is the hose for the water pilot. If it is open, the next thing that can be blocked is the oil cooler itself or the cooling water intake. First check the pilot hose.







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View attachment 127412

I'm just curious why I would be checking this? I get good water flow through the pilot outlets when I'm on the water...

 

[WREKS]

Then cooling does not seem to be a problem. I'll wait for the water test. As others have advised, I would check the area by the impeller for some lodged debris. Does not take much.

 

[AZMark]

I had a tiny stick get caught in the front side of my impeller before and it survived in there half a day on the water before I got it home, located it, and worked it out with a pair of pliers. It had polished itself into the shape of the pump housing and it seemed like it could have stayed there a very long time. It caused a noise/vibration that I thought was a bigger problem.

Edit: Yep, just like @WREKS just said. The stick in mine was about 2" x 1/8" and felt like it vibrated the whole boat.

 

[the MfM]

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[FLJetBoater]

I had a tiny stick get caught in the front side of my impeller before and it survived in there half a day on the water before I got it home, located it, and worked it out with a pair of pliers. It had polished itself into the shape of the pump housing and it seemed like it could have stayed there a very long time. It caused a noise/vibration that I thought was a bigger problem.

Edit: Yep, just like @WREKS just said. The stick in mine was about 2" x 1/8" and felt like it vibrated the whole boat.

do you have to take the bolts that connect through the hull to remove the pump housing or is it only the bolts further out? Any sealant when putting back together?

 

[sunbyrned]

This video explains it all.

 

[Scottintexas]

or this,
https://jdonalds.smugmug.com/Vehicles/Boats/Pump-Removal/i-NP8wfmz

The hardest part for me is the reverse bucket attachment, moving that spring/slide to disconnect, After a few minutes I always wonder if undoing the nut/bolt and removing the who attachment point is easier,

You don't want to disconnect the plate that attaches to the boat, the other 4 bolts and that will pull you bucket/wear ring/impeller shaft all at one time,

I never use any silicone or sealant to put it back together, I do put some grease on the impeller splines hoping to make removal the next time easier,

sometimes putting the impeller shaft back in you have to slightly rotate the assembly and firmly push to get the splines to meet up,

 

[AZMark]

do you have to take the bolts that connect through the hull to remove the pump housing or is it only the bolts further out? Any sealant when putting back together?

I didn’t remove anything to clear mine. I crawled under the boat on the trailer and reached up through the intake grate.