Help open waters around the corner

[Here-Kitty-Kitty]

My motor is running like [PoorWordUsage] Hopefully one of you guys will have an idea

Heres what is happening

When out of water and on the stand it runs just fine, but once I get it in the water and start driving the motor starts hesitating like its loosing all power. Then it will get up and go for a maybe 3-4 second then loose it. I replaced all the electrical,points, ect. I must be taking on water somewhere as the lower unit fluid was a little milky, ut I figure thats just a seal.

[Here-Kitty-Kitty]

Oh and I seemed to have a possible fuel leak somewhere under the hood, but that shouldn't have anything to do with the problem right?

[gregg52]

not a motor head here

but i think i would check fuel filters first

fuel leak could maybe have something to do with could be sucking air

but i'm just guessing you will get alot more opinions here !!!!

[pureinsanity]

Fuel leak is bad. When you say it runs fine out of the water. You mean just idling or you throttled it up in gear in a tub?

My friends motor had a fuel leak, bad gasket on the carb and a bad float. After that was all fixed it works good for as old as it is.

what does your float look like? is it an old cork float? you should be able to figure out where the fuel leak is just by pumping the bulb and see where the fuel squirts out.

[morepower02]

The first thing would be to take care of the fuel leak. If the problem still exists I would clean the carb. Is the engine pumping water good? Also a compression and leak down test would not hurt either.

[shawn1982]

How old is it and what kind of motor is it??? I have a 1962 johnson 10 horse that does that same thing. What i have learned is that it will troll down nice and u wont have a problem but when you give it the onion it does that same thing where it seems like it loses all power. I have learned to adjust the choke on it and lean it way out.. Seems to really help. Also it could be your gas leak and it sucking air. once it seems to lose power check your ball on your gas line. Might be empty? I will pump it back up and it will shove a little much gas into the motor for a bit but definatly helps. I think its time to get rid of it...its hard to fish when you have to hold the motors hand the whole time!!! HAHA!!

[Here-Kitty-Kitty]

I have no clue where the leak is on the motor can't find it. Just seems that there is fuel in the motor compartment. Ball and float are fine just replaced them in fact. Its a mid 70's Johnson 20hp.

Nick I'm giving it full throttle out of the water, and she runs and sounds like a champ. Got me all excited thinking that I fixed it until it get to the water. Also I'm using the earmuffs not putting it in a bin. It trolls slowly just fine until you give it gas.

[gregg52]

I try all the simple stuff first

filters...plugs..

i'm still bettin filters specialy if no resistancs it runs good then when in the water it wont go

still guessing but easy fixes and not much $$$

[luckycrank]

has it ever sat beached or on a boat lift ? the reason why I ask is we had a early 80 mercury that sat on a lift in shallow water and the exhaust would plug up with weeds and sand from time to time ran great at lower speeds but had no power on top end. when we brought it to the shop it ran flawless on the muffs with no load. however fuel is definatly priority if you know theres a leak. find that first both for safety and performance.

do you have a vacuumm gauge ? I read you replaced the float, I did not see anything about the needle and seat valve, is it sealing when the float in fully up? if it is worn it is possible for fuel to pass regardless of float position.

connest a vaccum gauge to the fuel inlet on the carb tip it so that the float is in the fully up position or up side down. ( best to have the carb off the engine)

apply say 15 inches of vacuum . does it hold it? yes needle valve and seat are good if no replace it!

[luckycrank]

you can also vaccum check your fuel pump diaphram too it should also hold vaccuum also. did you ever try sqeezeing the primer ball while wide open?

[boatfixer]

Lets start with the basics.

Compression. Have you done a compression test?

Spark. Spark on both cylinders at idle, mid range and WOT?

Fuel. Well you've said you have fuel leak. Yes, a fuel leak can cause you problems.

First thing i'd do is a compression test. Always the first thing I do. If you have low or uneven compression, tune ups, carb cleaning, plug replacements are all a waste of time and money. If you have good even compresion, then move onto to spark.

In your case, based on what you've described, I'd kind of lean towards a fuel related issue. Sounds like it is starving for fuel. But as I mentioned above, try a systematic attempt of narrowing down the possible causes by ruling out the basic and easy stuff.

[Here-Kitty-Kitty]

Thanks for the ideas guys. While messing around with my motor last night I noticed that I have an air leak coming from my top cylinder. Someone prior to me must have stripped out the spark plug hole and re tapped it. I new that it had been done do to the fact that there is a adapter on my plug, but every time I have changed it it seemed to be fine. Looks like over time I has worn out and there in enough space there to give me enough of a leak to be noticeable. Any ideas as to how to go about fixing such a problem, and could this be the culprit to my problems?

[Eelpout08]

poor performance only under a load is a classic low compression symptom. having a fuel leak could also cause the problems you are describing. under a no load condition the engine doesnt use nearly the fuel as when it is pushing a boat in the lake.

Start with a compresion test to see if it is worth putting any more money into. then i would replace all the fuel lines and filters, they are cheap insurance and it can be hard to see small cracks or leaking connections. also if the carb is clean make sure the float is adjusted correctly. as far as a stripped out spark plug hole about all you can do is try something like a heli-coil but even then the head should come off and you might just as well find a used one to put back on.

also i wouldn't recommend running an outboard past idle on those earmuffs. it really doesnt do much good anyway because any tuning other than at idle should be done in the actual conditions the motor will be run in.

[Here-Kitty-Kitty]

I'm guessing that the fuel leak is coming from the gap behind the spark plug. Is should have specified that the leak wasn't major or even steady, but enough that it was gumming up all the old oil.