MOJO ate an idler pulley

[Holdmybeer]

Title says it all.
Coming in for the day boat went into reduced power. 248* and check engine light....killed it quickly but hopefully no long term issues.
No smoke and raw water was still pumping.

Idler is gone. Nothing but the seized bearing left on the mount. Upper starboard side. Belt is still good but it's getting changed also. Water sheriff got us the rest of the way to the dock. Antifreeze burped through the overflow tank....

[larry_arizona]

248f isn’t enough to hurt anything.

Idler bearings are pretty common, but never happens a good time.


Sent from my iPhone using Tapatalk

[HFarr]

Had it happen to me before on a car, but not a boat. At least it's a pretty easily replacement part.

Sent from my SM-G781V using Tapatalk

[Holdmybeer]

I didn't think 248 was a problem but sure scares the crap out of you.

After looking at it, Only lost the overflow amount of anti-freeze. So not horrible, didn't boil like I thought it did at first.

I'll post pictures of the idler once I get it off. It's toast!

[Holdmybeer]

Here is what was left of it.

30576


I found the belt P/N 725901

Anyone have any idea how to find the idler pulley part number?
Indmar 1662357 is what I get off the Australian website.
Indmar 551246 is what I got off parts site.

I know 2015 had the extra lower idler pulley but not sure what to buy.

[Holdmybeer]

Hardware fixed.

Belt is a pain. Have to remove the 3 bolts on the crank pulley and pull the raw water pump away to get the belt around the crank.

Still need anti-freeze and run it at home before lake testing. But looking positive again.

30581

[KnoxMojo]

Did you have any other symptoms before hand? Belt squeal, high pitch whine, anything? Glad you got it fixed.

[Holdmybeer]

Did you have any other symptoms before hand? Belt squeal, high pitch whine, anything? Glad you got it fixed.

Nothing at all.
I thought I felt a little lag keeping surf speed but the water was a little choppy and with the paddlebwheel this has been normal.
I was hanging with the kids in the bow and wife was driving when it completely failed. Didn't hear anything out of normal. The belt was actually in good condition, no tears, cracks, or hard spots. Overheat scared me but didn't even smoke. Burped through the reservoir. Going to find out tomorrow how much I actually lost.

[Holdmybeer]

Coolant topped off. Ran on fake a lake in the driveway.
Temp climbed to 210 but it took some time and I revved it a little without the transmission engaged. Water flow was good. No smoke or burning smell. Only needed 1qt of coolant to replace what I lost.

I know I'm super sensitive to the issue right now. However, I don't ever remember seeing that temp when on a hose. I know higher than idle on the hose will cause temp rise since supply is much less than demand.

After getting to 240* could the thermostat be toast?

[HFarr]

I would replace the thermostat just for peace of mind. Not expensive and pretty easy to do.

Sent from my SM-G781V using Tapatalk

[BigOrange]

Yeah even on the hose I think mine holds 167 or 171 even if revved up a bit.

[Holdmybeer]

Ran it on the 3/4" hose today and removed all the timers and gardening stuff my wife has on this output.

Boat ran 35 minutes and only got to 210 then held. Thermostat opened at 160 as designed. The output hose from the thermostat housing never got hot enough to burn me but the hose was rock hard so flow and coolant were not an issue.

The fake a lake plunger I have is not the greatest but water was running through the raw system pretty good. No coolant any where and the reservoir stayed full.

We will see what happens at the dock tomorrow. Anyone know how to clear the SPN code? Or does this one require a dealer?

[jcarter20]

Hardware fixed.

Belt is a pain. Have to remove the 3 bolts on the crank pulley and pull the raw water pump away to get the belt around the crank.

Still need anti-freeze and run it at home before lake testing. But looking positive again.

30581


Sent from my iPhone using Tapatalk

[jcarter20]

Hardware fixed.

Belt is a pain. Have to remove the 3 bolts on the crank pulley and pull the raw water pump away to get the belt around the crank.

Still need anti-freeze and run it at home before lake testing. But looking positive again.

30581

I know this is an old post, but I was going to replace my belt as normal maintenance. Are you able to explain a little more in depth as to how you removed the raw water pump? Is it just the 3 bolts and it will pull out? Or is there more to it than that?


Sent from my iPhone using Tapatalk

[Holdmybeer]

Yep. 3 bolts, hub on pump pulls back just enough to run the flat belt through. Bolt pump back to balancer.

The bolts completely suck to remove. Mine had factory orange thread locker and the paint helping hold them.

Put a white towel under the engine where you are working. This way it catches them if you drop anything. By luck I had one down to protect my knees and it saved me hours with a magnet.

[jcarter20]

How do you loosen the belt tension? I saw online you put a 1/2” drive socket into the tensioner, but it doesn’t seem to move easily like the video I watched. Do I need to remove or losses the hex head bolts to allow it to swing?

I also think I will replace that idler wheel. Do you happen to have a part #? https://uploads.tapatalk-cdn.com/20250322/ef01a2ed3d49b371d8498080be50f879.jpg


Sent from my iPhone using Tapatalk

[jcarter20]

https://uploads.tapatalk-cdn.com/20250322/fa94b5b9a79ee536fdeabd932c92f621.jpg
It had a little wobble, so I was going to replace it while I have the belt off.


Sent from my iPhone using Tapatalk

[Holdmybeer]

The half inch drive goes in the square hole on the right. My ratchet did not give me enough leverage. I used a 24" breaker bar and it was easy.

[Holdmybeer]

https://uploads.tapatalk-cdn.com/20250322/fa94b5b9a79ee536fdeabd932c92f621.jpg
It had a little wobble, so I was going to replace it while I have the belt off.


Sent from my iPhone using Tapatalk

This the pulley that failed on me. The bearing seized and the belt ate the plastic.

[jcarter20]

Here is what was left of it.

30576


I found the belt P/N 725901

Anyone have any idea how to find the idler pulley part number?
Indmar 1662357 is what I get off the Australian website.
Indmar 551246 is what I got off parts site.

I know 2015 had the extra lower idler pulley but not sure what to buy.

Was the P/N the 551246? I am having the same problem trying to figure out the part number. I see that one on Inboard Online. Just want to make sure that is correct.


Sent from my iPhone using Tapatalk

[Holdmybeer]

Was the P/N the 551246? I am having the same problem trying to figure out the part number. I see that one on Inboard Online. Just want to make sure that is correct.


Sent from my iPhone using Tapatalk

That was the part number I used for the pulley. I have a local-ish Indmar dealer that ordered both the pulley and the belt for me.
Check though...your looks to be smooth not grooved.

Smooth part number is 551499.

Don't use my belt number. Your 2018 has a different part number and slightly different routing.

[jcarter20]

Awesome. Thank you! Yes mine is smooth.


Sent from my iPhone using Tapatalk