Hit a sand bar at 1/4 throttle. Bogging now?

[jimmbo]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

I've seen them partialy sheared, looking like an offset key. When that happened on my dads 40 hp johnson the key would rock slightly in the keyway on the crankshaft. Those twin cylinders had huge flywheels on a small taper. I think it moved around a bit, on rapid rpm changes. It did come loose one time, after it had been in the shop, the engine jumped like it had struck something, more violent than a clutch dog jumping. Fortunately the recoil starter kept it from coming right off.

 

[Sandor27]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

You need to check for a spun prop hub. Make a sharpie marker line on the shaft and on the prop. Run WOT for a little bit. Then look to see if the mark still align. If mis-aligned, time for prop rebuild or new prop. If aligned start looking elsewhere for the problem.
Are you still at the same trim angle? Does the prop spin smoothly and easily in neutral?

 

[Ki Ki]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

So mechanic so far thinks the impeller is the issue. He replaced that, but is trying something else. Would this make any sense for bogging and slower speed at wot?

I don't get it. Still had a good pee stream!!

 

[Ki Ki]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

Also, any ideas on cost to replace I should expect?

Fortunately we didn't run it much more than 10 minutes back to dock. Impeller doesn't make sense to me if it was peeing water. Why would it only bog at WOT and lose speed?

 

[Scurvy Knave]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

no. impeller wouldn't cause that. Check prop hub as mentioned in #22 (if applicable to your motor). Also, visually check trim, fuel lines, etc. Look at flywheel key for damage or offset.

 

[Ki Ki]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

I wonder why he replaced impeller then!?

Said he was checking other stuff. I so know impeller hasn't been replaced in past couple of years. Good to do regardless?

 

[classiccat]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

I wonder why he replaced impeller then!?

Said he was checking other stuff. I so know impeller hasn't been replaced in past couple of years. Good to do regardless?

giving your mechanic the benefit of the doubt, he may have changed as a precautionary measure since the water pump may have been damaged from "ingesting" sand.

 

[Ki Ki]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

giving your mechanic the benefit of the doubt, he may have changed as a precautionary measure since the water pump may have been damaged from "ingesting" sand.

Yah

 

[Ki Ki]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

Any other thoughts on this?

 

[vendingworks]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

no. impeller wouldn't cause that. Check prop hub as mentioned in #22 (if applicable to your motor). Also, visually check trim, fuel lines, etc. Look at flywheel key for damage or offset.

I hit one at full speed! I drove the gear deep into the pinion gear and would not come out of forward in lower unit. Yours may be just wedged a little, running tighter than where it is supposed to be. Check to see if you lost the slack that should be there. We just took it apart fixed it ! Latter we had to rteplace the seals.

 

[jimmbo]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

This is a long shot. When I was a kid we hit something with my dads 5 1/2 hp a short time later the boat was slower ,unable to plane. Inspection showed all the oil in the gearcase was gone. propshaft and bushing had worn to a new pattern and shaft could only be hammered out. New gears, bearings shafts and all was good again. Like I said a long shot

 

[Ki Ki]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

Update. Picked up the boat from the shop. Ran great!

 

[vendingworks]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

Update. Picked up the boat from the shop. Ran great!

Ok, great! What was wrong??? Thanks

 

[Ki Ki]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

Ok, great! What was wrong??? Thanks

The impeller was bad. He said that it caused it to run warm. Fortunately we headed straight for the dock and loaded it on the trailer after hitting the sand.

 

[Ki Ki]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

The impeller was bad. He said that it caused it to run warm. Fortunately we headed straight for the dock and loaded it on the trailer after hitting the sand.

It actually is going faster now on GPS than ever. Maybe this Impeller wasn't 100% for a while?

 

[Tim Frank]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

The impeller was bad. He said that it caused it to run warm. Fortunately we headed straight for the dock and loaded it on the trailer after hitting the sand.

So you've had two impeller changes since hitting the sandbar?

 

[Ki Ki]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

Nope, just the one. I didn't want to mess with anything so I took it to a great mechanic that thoroughly went over it and replaced the impeller upon inspection.

So, isn't the impeller something that should be changed periodically anyhow? Not sure last time it was changed.

 

[nwcove]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

if you have a motor and you dont have any idea when the impeller was last changed.....its overdue!!!

 

[Ki Ki]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

The mechanic said due to the impeller damage it caused the engine to run warm at WOT and bog. I read online there's a thing called "limp mode". Is that what may have happened? Did a test drive and it ran perfect with new impeller and actually gained 1 mph. Apparently it was pumping a little water, but not enough. Glad we went straight to the dock.

 

[bobsquatch]

Re: Hit a sand bar at 1/4 throttle. Bogging now?

Gotta love it when it is something simple and the mechanic is upstanding and honest and everyone comes out happy in the end. It is also a perfect illustration that even with expert advice the advantage goes to the person looking at the unit. I do a lot of shooting in the dark with guidance from experienced people and it helps me so much but we can't win every time.