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

[Ki Ki]

We were going about 1/4 throttle. 30 hp Johnson Outboard. Hit sand bar.

Runs in forward and reverse fine, but about 5 mph slower at wide open throttle and bogs when wide open a bit ocassionally.

Any ideas ?

 

[jimmbo]

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

"Hit sand bar" is vague. Soft sand, hard sand, gravel, rocks? Did motor kick up, or did it just sound like it was labouring for a sec or two? Was the entire boat stuck? A damaged prop could account for the drop in speed.If the boat was stuck on sand, maybe the pitot is plugged with sand, making it look like the boat is slower. Bogging isn't usually caused by hitting sandbars, unless you're still hitting them. If the impact was severe enough it could cause the key for the flywheel to shear and cause timming issues

 

[Ki Ki]

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

"Hit sand bar" is vague. Soft sand, hard sand, gravel, rocks? Did motor kick up, or did it just sound like it was labouring for a sec or two? Was the entire boat stuck? A damaged prop could account for the drop in speed.If the boat was stuck on sand, maybe the pitot is plugged with sand, making it look like the boat is slower. Bogging isn't usually caused by hitting sandbars, unless you're still hitting them. If the impact was severe enough it could cause the key for the flywheel to shear and cause timming issues

I'll be more specific. A thick sand. Bumped it. Engine lifted up. Bogged for second never stalled. Then at wide open throttle we were about 5 mph slower and bogged quite a bit. Propeller in good shape and so is lower unit. Confused.

 

[Tim Frank]

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

If the boat was stuck on sand, maybe the pitot is plugged with sand, making it look like the boat is slower. Bogging isn't usually caused by hitting sandbars, unless you're still hitting them. .....

^^^^^
Do you have a speedo on the boat or are you calculating speed with a GPS?

 

[Ki Ki]

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

^^^^^
do you have a speedo on the boat or are you calculating speed with a gps?

gps.

 

[xjdriver]

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

Mabey when you hit the sandbar it disturbed a piece of crap in the carb bowl and now its restricting the main jet? Just a thought

 

[Ki Ki]

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

Mabey when you hit the sandbar it disturbed a piece of crap in the carb bowl and now its restricting the main jet? Just a thought

Maybe! Any other ideas?

 

[Tim Frank]

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

Maybe check the bottom of the boat to see if anything has been bent etc.

 

[Ki Ki]

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

Maybe check the bottom of the boat to see if anything has been bent etc.

Checked that, all seems good.

 

[bonzoscott]

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

I don't think this would make a difference of 5 MPH but you probably want to tear apart and inspect impeller. She may have sucked up a whole bunch of sand mud. Who knows, you may find the 5 MPH loss. Only other thing is maybe it distorted your prop.

 

[Ki Ki]

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

I don't think this would make a difference of 5 MPH but you probably want to tear apart and inspect impeller. She may have sucked up a whole bunch of sand mud. Who knows, you may find the 5 MPH loss. Only other thing is maybe it distorted your prop.

Could the bogging be an impeller issue too?

 

[Tim Frank]

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

Before the sandbar incident, when was last time you checked top speed? Maybe the two are not actually related.
Also, is this power T&T or manual?
Could you have thrown out the tilt when you hit the bar?

 

[Ki Ki]

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

Before the sandbar incident, when was last time you checked top speed? Maybe the two are not actually related.
Also, is this power T&T or manual?
Could you have thrown out the tilt when you hit the bar?

Going to marine mechanic.

 

[Ki Ki]

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

I had someone else mention a sheared flywheel key too, which could cause it to bog at wide open throttle. If I get this done at a shop are we talking major bucks on a 30 hp 1995 Johnson? What kind of repair cost should I expect IF that's it?

Why would a sheared flywheel key just affect it once in a while at wot? Also, slow the speed of the boat?

 

[Ki Ki]

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

I had someone else mention a sheared flywheel key too, which could cause it to bog at wide open throttle. If I get this done at a shop are we talking major bucks on a 30 hp 1995 Johnson? What kind of repair cost should I expect IF that's it?

Why would a sheared flywheel key just affect it once in a while at wot? Also, slow the speed of the boat?

Anyone?

 

[xjdriver]

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

Im pretty sure a sheared flywheel key will couse issues ALL the time, i would think mostly at wot
If it is the key, itt would be an easy fix, jus pop the flywheel off, and replace key

 

[jimmbo]

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

Bogging at WOT can be a fuel issue. Any chance the fuel line has been pinched, kinked, stretched, during or after contact with the sandbar?
A sheared flywheel key could result in incorrect, inconsistent timing

 

[Tim Frank]

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

Bogging at WOT can be a fuel issue. Any chance the fuel line has been pinched, kinked, stretched, during or after contact with the sandbar?
A sheared flywheel key could result in incorrect, inconsistent timing

Given the description by the OP, the symptom might be incorrect...but CONsistent timing.
Maybe someone can weigh in on whether you can "partially" shear a key. A shift of 4 or 5 degrees would sfift up the timing....probably enough for this complaint.

 

[JSGOLD]

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

I'm just offering a guess but is there possibly a shear pin on the prop or in the lower unit that would break but the prop remain on the lu? It might be spinning but slipping internally or at the prop. Maybe a broken shaft in the lower unit?? Just guessing......

 

[bonzoscott]

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

If the motor is running well at everything except WOT, it's not the flywheel key. Something else is wrong here. Need a better observation and description. Losing 5 MPH could be the load you put on the boat the next time, like the cooler fuller or the girl bigger....
Easy way to check the key is pull the flywheel and have a look. You can bet a shop will get a couple hours outta that - $90 Hr