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

[Big Jay]

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

Great thread...

Thank you for posting, the result was unexpected....

Valuable information

 

[Ki Ki]

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

Great thread...

Thank you for posting, the result was unexpected....

Valuable information

We were just as happy as anyone too, no problem. He's a great mechanic, always pretty much a wait list to get your boat looked at by him since he's so good and reasonable. I didn't think the price was bad. After diagnosing the issue and testing it, he discovered the bad impeller, and replaced that and tested it again for $100 total.

 

[Ki Ki]

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

Now I'm curious about this "limp home mode" that the engine may have went into. Anyone heard of this? I haven't until now. So apparently, the engine sensed it was getting warm at WOT. It bogs down to prevent getting too hot, but allows you to run at a slower operating speed to get to the dock. So when the impeller was damaged, it went into this mode presumably. The impeller was still spitting water, but not nearly enough for WOT. I took it out, as mentioned, and it ran like a charm and the 'pee stream' was stronger than it ever has been. Again, it's a 1995 Johnson 30 hp outboard, didn't even know engines had a limp mode.. I guess regulated by the power pack?

 

[Tim Frank]

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

Now I'm curious about this "limp home mode" that the engine may have went into. Anyone heard of this? I haven't until now. So apparently, the engine sensed it was getting warm at WOT. It bogs down to prevent getting too hot, but allows you to run at a slower operating speed to get to the dock. So when the impeller was damaged, it went into this mode presumably. The impeller was still spitting water, but not nearly enough for WOT. I took it out, as mentioned, and it ran like a charm and the 'pee stream' was stronger than it ever has been. Again, it's a 1995 Johnson 30 hp outboard, didn't even know engines had a limp mode.. I guess regulated by the power pack?

Some newer and larger motors have this....a 1995 30 HP, I don't think so.

 

[Ki Ki]

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

Must've just bogged from getting hot and ran slower with the impeller broke. Glad it's fixed and working well.

 

[Ki Ki]

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

So, this was peculiar. It ran great first time out at WOT after the new Impeller. This time, the bogging returned at WOT after about 10 minutes of continual cruising at WOT. I haven't a clue?

Engine had a perfect pee stream and wasn't warm to the touch. I thought I smelled some kind of odd smell from the motor, but it could've been from shore.

The bog seems progressive. It starts with some slight dipping that you can hear but gets to the point where it almost stops in its tracks, but doesn't stall out.

It runs find anything less than full throttle.

Any guesses ?

 

[Ki Ki]

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

Another question to my previous post: so, the engine was warm but sat while fishing for about an hour.

We did not repump the fuel ball. Is that necessary after its already ran? Could it of been from not having the ball repumped?

 

[jimmbo]

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

10 minutes? have you tried running it with the fuel tank cap loose?

 

[Ki Ki]

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

10 minutes? have you tried running it with the fuel tank cap loose?

That's interesting. No I haven't. In fact, the tank is one of those duratank 6 gallon tanks that has no adjustable valve. Supposedly I e read it vents itself, but sure doesn't seem that way to me.

 

[Ki Ki]

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

Any other guesses? Can I loosen the gas cap while boating to let air escape so long it's not raining out?

 

[Tim Frank]

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

You aren't trying to let air ESCAPE....you are trying to let it INTO the tank....so that the system isn't under a vacuum.

 

[Ki Ki]

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

You aren't trying to let air ESCAPE....you are trying to let it INTO the tank....so that the system isn't under a vacuum.

What's your thoughts on those Duratanks? It's a nice tank, but it supposedly releases without a manual vent. I prefer a manual vent to be honest. It seems more reliable. Should I order a new tank or just loosen the gas cap?

I would be happy to just order a SeaSense or comperable 6 gallon tank with manual vent and new fitting for a Johnson motor to go into the tank. That seems most logical and saves a trip to the shop for a $40 tank.

Also, any idea why it would only do this at WOT?

 

[Ki Ki]

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

What's your thoughts on those Duratanks? It's a nice tank, but it supposedly releases without a manual vent. I prefer a manual vent to be honest. It seems more reliable. Should I order a new tank or just loosen the gas cap?

I would be happy to just order a SeaSense or comperable 6 gallon tank with manual vent and new fitting for a Johnson motor to go into the tank. That seems most logical and saves a trip to the shop for a $40 tank.

Also, any idea why it would only do this at WOT?

Would a generic vented gas cap work with this DuraTank or no?

 

[jimmbo]

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

OMC for years made tanks with unvented filler caps. The tank was sealed until the fuel line was connected. Worked fine.
If the tank vent is almost completely blocked it still might allow enough air for low fuel demand operation but at WOT, where fuel requirements are much greater, the venting could be less than needed.

You did say the engine did flip up upon the impact. If the motions were violent enough then maybe it did a slight adjustment to the float in the carb

Without being able to have the engine front and center to be able inspect it... It sounds most like a fuel delivery issue, but a thorough check of ignition system should also be done

 

[Ki Ki]

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

OMC for years made tanks with unvented filler caps. The tank was sealed until the fuel line was connected. Worked fine.
If the tank vent is almost completely blocked it still might allow enough air for low fuel demand operation but at WOT, where fuel requirements are much greater, the venting could be less than needed.

You did say the engine did flip up upon the impact. If the motions were violent enough then maybe it did a slight adjustment to the float in the carb

Without being able to have the engine front and center to be able inspect it... It sounds most like a fuel delivery issue, but a thorough check of ignition system should also be done

That makes perfect sense. The tank does leak near the fuel connection when it gets really hot out I've noticed. Maybe it is blocked partially?

is there any reason not to switch to a manual vent tank? Can't see why not?

 

[Ki Ki]

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

is there any reason not to switch to a manual vent tank? Can't see why not?

Anyone?

 

[Ki Ki]

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

That makes perfect sense. The tank does leak near the fuel connection when it gets really hot out I've noticed. Maybe it is blocked partially?

is there any reason not to switch to a manual vent tank? Can't see why not?

Any info from the resident experts would be greatly appreciated.

 

[keefallan]

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

I don't know about the fuel tank stuff. But have you checked/changed the fuel filter(if you have one)? Maybe the carb is clogged?

 

[Ki Ki]

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

I don't know about the fuel tank stuff. But have you checked/changed the fuel filter(if you have one)? Maybe the carb is clogged?

Well would the fuel filter just occur after running for a duration? Seems like something, such as fuel tank, is building up pressure enough where after it runs constant at WOT it creates the vacuum.

I'd like to know if any 6 gallon vented tank would work.

 

[Tim Frank]

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

10 minutes? have you tried running it with the fuel tank cap loose?

You have to help us out here and answer the questions, be more systematic....and maybe show a bit more patience.....

At this point after reviewing the thread, I have no idea why you are focused on the gas tank....and you haven't even bothered doing what this responder suggested.....as as as i can tell

I have never heard the term "Duratank", but if it is simply one of the ubiquitous OMC-OEM tanks that are everywhere, no way would I swap that for one of the new plastic ones; a down-grade for sure!

If you want a manual vent ....get an OMC cap WITH a manual vent for your current tank....much better than a plastic option.

If the tank/cap combo is a problem, when you get the drop in RPM, immediately check the bulb and if it is sucked flat....quickly open the tank cap and listen for a "hsssssssssssssssssss" as air is sucked in.
If that condition does not exist, I'd look elsewhere.

You can throw parts at it as much as you like, but if you are not systematic in troubleshooting, your bankroll will simply decrease as your frustration level increases.