Sand in the motor

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Uncle Krusty

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Well, I ran aground on a sand bar and sucked a lot of sand into the motor, a 2003 Honda B15D. I've run it on the muffs and not gotten anywhere near all the sand out. I took it out briefly, but it bogged down and wanted to die. When I put it on the muffs it ran well at idle and then just quit, but would restart. I didn't get any kind off overheating alarm, but I'm not sure this motor has one. I pulled the t-stat and there is a lot of sand in there. I'm thinking of running water down the hole, as well as running it in a tank. I have also thought of running it with the t-stat out for a just while, but I'm unsure of the consequences of it if would even help.

I'd really like to avoid another big shop bill. Any thoughts or experience with this?
 

DaleH

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I've never any OB whereI needed to flush that much, but I'd say the sand wouldn't be causing the bogging issue. To me, it would be cheap insurance to perform a new waterpump/impeller service, which you can do yourself for parts, maybe $50-60. If you don't have it, I bet a PDF version of the factory service manual could be had online for $20 or less.

I'd also keep running it in a big barrel (NOT muffs!) with fresh water changes and without the t-stat. Just install it before you go out to use it. Also follow the pee port/discharge hose and remove at both end to make sure any gunk gets out of the block.

Not sure of the Honda, but on some OBs that pee exit hose comes direct out of the block, so you can remove the hose there (while running in a barrel) and let it stream overboard, plus you can watcg for any clogging, as sometime the ports clog up where the fitting is threaded into the block.
 

Uncle Krusty

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Does it make sense to hose water through the open t-stat hole? It's got a lot of sand in it.
The pee hole hose is out of reach.
I was going to run it in the can, so I'll give that a try and report back. Hey, if I'm running it in a tank will I just suck the sand back in? I guess there would be less and less if I keep changing the water.
 

DaleH

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Uncle Krusty said:
Does it make sense to hose water through the open t-stat hole? It's got a lot of sand in it.
I think only Pappy is qualified enough to answer that question ... and a good question it is. Maybe you could PM him?

Hey, if I'm running it in a tank will I just suck the sand back in? I guess there would be less and less if I keep changing the water.
Sand being heavier should settle to the bottom, as long as you don't put it in gear. Or you could run for a few minutes, shut off and let settle, repeat ... or change out the water. If the barrel is deep enough and the pickup is a foot above the bottom of the barrel, I don't think you'd ingest any.

Or take to nearest body of water and run in the water, idle to fast idle speeds, and if confident, fast, as T-stats usually open getting to 2K or higher RPMs, depending on the OB of course. I'd try to get it out via the t-stat port, so as not to follow through the motr and pulg the overbaord discharge port. Again, I'd try PM'ing Pappy, as I've not ever needed to do one like you're facing.

That's a lot of sand!!!!!! And I run in sandy saltwaters!
 

Uncle Krusty

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That's a lot of sand!!!!!!

I tried to motor off the sandbar, duh. It wasn't until later that it came to me that it had to be sucking sand into the cooling system. We both had to get out and push. Not the safest feeling in a big bay with strong tides.

I ran the motor for brief periods with the t-stat out, then put it back in and idled it for 15 minutes, in the tank. It ran flawlessly, but the telltale water never warmed up. Bad t-stat, or just not idled long enough? I vote for bad t-stat, but what do I know? I suppose I should have a look at the impeller? That may exceed my pay grade, but I don't want to wait for the shop to do it. Nor do I want to pay them. Again.
 

MrGiggles

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Uncle Krusty said:
Does it make sense to hose water through the open t-stat hole? It's got a lot of sand in it.
The pee hole hose is out of reach.
I was going to run it in the can, so I'll give that a try and report back. Hey, if I'm running it in a tank will I just suck the sand back in? I guess there would be less and less if I keep changing the water.

If that motor was in my shop, I would do exactly that. Drop the lower unit, you will likely need a water pump anyway from eating all that sand, and flush through the thermostat hole as much as I could.

The passages get smaller as you go up, best to go from the top down (assuming the lower unit is removed). Flush it out the same way it came in.

I would also replace that thermostat once you get everything clean. Doesn't take much to stop them from opening or closing properly.

Also remove the grates from the lower unit if you can, and make sure the passage going to the water pump is clear.
 

DaleH

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Uncle Krusty said:
It ran flawlessly, but the telltale water never warmed up. Bad t-stat, or just not idled long enough? I vote for bad t-stat, but what do I know?
Doubtful idle speed would even allow it to open ...

Glad Mr Giggles concurs with your path forward! Go fix it :)
 

Uncle Krusty

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Can I remove the lower unit in one piece? I should also check the impeller and whatever it spins in, but I may not be competent to do that. I'll look into it. I have checked the water intake grates and they are fine.

I still wonder why the motor ran the way it did. At higher throttle it bogged down, maybe like there was an obstruction. I'm thinking it overheated and the limiter or whatever it is kicked in.

I am no mechanic!
 

Pappy

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Keep the gearcase on for now.
Thermostats can be stuck open from sand and debris. Take a look at the seat when you have it out next time.
Yes you can flush pressurized water into the thermostat area to flush what you can out of it. You can also run it in the tank with no thermostat.
See if that works.
When you do pull the gearcase to check the pump put a hose on the water tube and force water through the cooling system that way. Lots more pressure and volume than the pump will create at idle or part throttle in the tank.
Replace the impeller if necessary although they are pretty tough when it comes to sand. Replace the housing if it is melted to the stainless cup or if there are grooves that your fingernail hangs in.
 

Uncle Krusty

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I've flushed the motor through the t-stat hole. Got a lot of sand out, with best results by flushing until the system was full, then letting it drain completely. I did this until no more sand came out, or just a few grains which I figure will get flushed during operation. I am now removing the lower unit.
The water pump part looks straightforward. Do I have to remove the prop and housing and a bunch of other stuff to do this? I'm thinking not, but why would the shop manual say to remove it?

The lower unit oil was pretty chocolatey looking. It was pressure tested by the shop just two weeks ago, so my sandbar adventure must have done something in there. I am currently struggling with a very tight, rounded off nut located such that I can't get a socket on it. The shop had to drill out one of the bolts and I think it was this one and they reused it. I've already made it worse by using a cheapo 10mm box end wrench that was a little loose on the nut, although it worked on the other nuts. I'm headed out to get a better quality wrench and some penetrating oil. I'd use heat but there is a nylon core to the nut and I don't want to make it even worse.

Regarding how the engine ran, it felt like a spun propeller after getting afloat again, and much the same with a new prop the next day.
 

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