Help Please

[SeanC]

I changed the impeller on my 2006 F250 for the first time. Run on muffs and in a tank of water. No flow from tell tail. No water through the upper flush connection and no water from exhaust when on muffs. Can’t see exhaust in tank. When I remove the lower unit and attach a hose to the pipe that comes off the water pump and run the motor all as expected. Water from tell tail, exhaust and upper flush connection.

Checked o-rings are seated. Impeller is keyed onto the drive shaft and rotates when drive shaft is turned. Impeller arms curved in correct direction. Drive shaft is turning prop when in gear. Everything says it should be working. Maybe low water pressure from hose when run on muffs, but same in the tank? If there isn’t enough pressure from the hose using the muffs and water isn’t reaching block then I would have expected to have over-temp alarms in the past.

No blockages between water pick-ups and pump. No blockages after pump.

If no one has any other ideas I suppose I could run the motor to see if I get an over-temp alarm and then most probably need to replace the impeller again.

Any thoughts?

Thanks.

 

[OMER]

this is a known issue with Yamaha engines.it does not work with a Muff.Use a barrel, the water level should be an inch or more above the cavitation plate.
The water pump must be submerged.

 

[OMER]

like that

 

[seasick]

If I mad ask, have you ever run the motor on muffs before the impeller change? If so, did it do the same thing? Right now, you have no reference point.
No water out of the flush port doesn't mean a lot. It should not be left disconnected though. No water out of the telltale may not be an issue either on muffs. In addition, sometimes it takes a while for the stream to flow. If none in a minute, I would be concerned.
Regarding the point of running it to see if you get an alarm: I don't like doing that. I prefer to run with the cowling off and use an IR thermometer to monitor t-stat housing temps. They should level off at around 145 or so. If there is little water flow, the heads themselves will heat up quickly also.

 

[OMER]

If I mad ask, have you ever run the motor on muffs before the impeller change? If so, did it do the same thing? Right now, you have no reference point.
No water out of the flush port doesn't mean a lot. It should not be left disconnected though. No water out of the telltale may not be an issue either on muffs. In addition, sometimes it takes a while for the stream to flow. If none in a minute, I would be concerned.
Regarding the point of running it to see if you get an alarm: I don't like doing that. I prefer to run with the cowling off and use an IR thermometer to monitor t-stat housing temps. They should level off at around 145 or so. If there is little water flow, the heads themselves will heat up quickly also.

yes.when i bought the boat, i wanted to run the engine with muffs,as i did with the suzuki engine of my BW.there was no water flow and after several minutes the temperature alarm went on. I thought that the water pump was not working.I contacted my Yamaha seller, I explained to him that the water pump was not working ,he is also Suzuki seller.He told me that the muffs worked well on a Suzuki but not on a Yamaha. He told me to take a barrel and fill it as in the picture.With the barrel, everything is back to normal, the water pump has been running for two more years,I changed it this year for safety.

 

[seasick]

In a way, that's good. I have had similar issues on muffs that were related to lower then optimal water flow through the hose due to a small diameter hose, too long a hose, or just low water pressure at the spigot.
Some Yami motors also have a second set of water inlets on the lower unit. In those cases, some folks put a piece of tape over those inlets. That helps the water pressure presented to the pump. If you can get a big tub or a barrel, it would help but first check that you have pretty good water pressure and flow at the end of the hose. I have also found that the corrugated hoses that shrink when there is no pressure, don't pass a lot of water volume and have caused overheats on motors that normally run fine on a regular hose and muffs.

 

[wspitler]

In your picture the water pump impeller is mostly above the water level and may not have primed. I would put the boat in the water and I'll bet you'll find it works good although the tell tales have a habit of getting clogged up with bugs.

 

[Shannon C.]

These work well.

 

[seasick]

Where did you get those cuties?

 

[Shannon C.]

Where did you get those cuties?

Amazon, great product. The frame is 1/2 pvc that can be disassembled and the bag is sandwiched together for storage, takes up very little room.

 

[seasick]

I can't find it. Do you have a product name?

 

[Shannon C.]

YACHT CLUB BURGEES - Burgee Shoppe

One stop source for Burgees, Flags and Race Committe supplies

www.burgeeshoppe.com

Outboard Motor Flushing Bag Model DPB3 for Engines up to 250 HP.
It looks like there out of stock on Amazon. This is the only place I could find them.

 

[seasick]

Thanks for the link.

 

[SeanC]

like that
View attachment 13018

Thanks. My tank wasn't that deep.

 

[SeanC]

Thanks everyone. I suspected everything was OK. Nice to have it confirmed.

 

[Parthery]

I’ve seen hot exhaust blow a hole in a plastic trash can. I wonder what those bags are made of.....

 

[Shannon C.]

I’ve seen hot exhaust blow a hole in a plastic trash can. I wonder what those bags are made of.....

I’m not sure, I’ve had them for a year and usually flush for 20-30min and never seen any sights of weakness. The water in the bags are definitely warm but not hot to the touch as the is a constant stream of cold water coming in from the hoses.

 

[SeanC]

If I mad ask, have you ever run the motor on muffs before the impeller change? If so, did it do the same thing? Right now, you have no reference point.
No water out of the flush port doesn't mean a lot. It should not be left disconnected though. No water out of the telltale may not be an issue either on muffs. In addition, sometimes it takes a while for the stream to flow. If none in a minute, I would be concerned.
Regarding the point of running it to see if you get an alarm: I don't like doing that. I prefer to run with the cowling off and use an IR thermometer to monitor t-stat housing temps. They should level off at around 145 or so. If there is little water flow, the heads themselves will heat up quickly also.

Haven't had the boat long and have been using just the the flush port. Decided to get muffs and first time I used them was after the impeller change so yes had no reference for before impeller change.

 

[Ky Grady]

100 Gal. water trough from Tractor Supply works great. Better than the muffs and tank is thick so no chance of blowing a hole.

 

[SeanC]

Hadn’t thought of a water trough. Perfect shape.

So last weekend was the first weekend I could take the boat after some restrictions were relaxed. Was a long weekend. Planned to go on Friday. Weather was perfect but spent all weekend chasing down a problem I didn’t have.