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1996 60hp Mercury Stalls in water no out Please help

psless

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"I recently bought a jon boat

"I recently bought a jon boat with a 60hp mercury on it. The guy I bought it from is a marine mechanic and said he totally rebuilt the carbs. Here is the probelm.

When I have the hose hooked to the motor it runs great. I can gas it full throttle in neutral, forward, and reverse. The problem is when I put it in the water and put it into gear. When I try and go full throttle then it bogs down and cuts out. It only lets me give it a little gas and put along. When I push further on the throttle it bogs out. The same thing happens in reverse on the water. If I put it in neutral on the water it will let me rev it up fine. What could this be?"
 
"Gday Patrick
First of all no


"Gday Patrick
First of all not full throttle tests in a no load situation or you may be looking out for a new powerhead. Sounds like a high speed ignition problem but try pumping the primer bulb and hitting the choke when the fault occurs if the engine pick up it’s a fuel problem if it cuts out probably an ignition problem. As always do the usual tests comp, sparkplugs, filters etc. A service manual will give you the specs and test procedures for the ignition system.

Cheers Spanaman"
 
"I took it back to the guy tha

"I took it back to the guy that I bought it from and we did a compression check (125 on all cylinders), spark was good, and filters looked ok. He then started the engine and began disconnecting a plug to see what would happen. Only when he disconnected the bottom plug did the engine cut off. He said it was b/c the top two shared a carb.

After all of that he was convinced it was the carbs. The bottom carb leaks a little fuel from the screw on the bottom, or at least that is where the fuels is collecting and slowing dripping from. Maybe a drop every 30 seconds only when engine is off.

SHould we take the carbs off and clean?"
 
"Isn’t your engine a 3 cylinde

"Isn’t your engine a 3 cylinder with 3 carbs, 1 carb per cylinder? (if so, no carb sharing goin on here). You shouldn’t have a fuel leak engine running or not, take off the air box prime up the fuel system and see if you can see a leak from a fuel line or something, you may have to remove ur oil tank to get a better view. It would be a good idea to remove and clean the carbs. Remember this engine has a high and low speed ignition system (may have good spark at idle but not above 1500rpm), so if doin the carbs doesn’t fix it then ur best to look at this next."
 
Thanks for your help Spanaman.

Thanks for your help Spanaman. Yes the engine has 2 carbs for 3 cylinders. It looks like the leak is coming from the screw on the bottom of the lower carb. I will give the carbs a good cleaning and then see how it runs. Should I replace any components while I have the carbs out? Oh one last thing. This engine has no oil tank. I have to mix the oil in the gas. Do you think it was removed?
 
"Then your engine might be an

"Then your engine might be an 86 not 96, while the carbs are off check that the reeds are intact and closed. Since the engine is probably a little older then we first thought it maybe a good idea to replace the needle and seat and all of the gaskets, check that the floats actually float and make the necessary adjustments. Check ur fuel lines replace any filters and clean fresh fuel of course. I thought being a 96 model that I would have had oil injection hence the oil tank, but it can’t be a 96 model since the 96 model has 3 carbs."
 
The guy told me it was a 96.

The guy told me it was a 96. I think they may have taken the oil injection off. I can take pics of the motor if you would like. GOOD NEWS!!! We took out the main jet/plug and it was totally clogged with debris (top carb). We cleaned it out and the boat ran beautifully today. There is still a little drip coming from the lower carb's bottom throttle shaft spring. Is it possible to have fuel leaking out of that or do you think it is leaking from somewhere else and collecting at that spring? I guess I could try changing the throttle shaft seal.

Thanks so much for your help. You have been great!
 
My derial number has 96 in it

My derial number has 96 in it so I hope its a 96. The serial number is 0B396055 Model 1030412GD. Is that an 86?
 
"After a little reseach I thin

"After a little reseach I think my motor is an 89. The saga continues. Well after some investigation I found out where the leak is coming from in the carbs. When I prime the bulb the little tubes that are in front of the venturi and kind of an angle towards the front of the carb begin to leak fuel out. It takes a couple of seconds but then both carbs start leaking. Here is a link to a picture that shows where the little tubes are that I am talking about.

http://i64.photobucket.com/albums/h161/psless/carbleak.jpg"

What do you think?"
 
I think I figured it out. I l

I think I figured it out. I loosened the screw on the throttle shaft on the top of the top carb and it let the carb shut a tiny little bit. I think the throttle was a little tiny bit open and it was allowing the gas to leak out. Is that possible?
 
"Sorry for the delayed reply.

"Sorry for the delayed reply. It is possible to have fuel leaking from a throttle shaft especially if it or the carby is worn, you could try a throttle shaft seal. Although on reading ur last two posts it seems to me that you may have an issue with the bottom carby flooding particularly if fuel is coming out that tube, you should have replaced the needle and seats (and the seat gasket) and adjust ur float level when doin ur carbs (reference no 3 & 4 on ur pic I think), both throttle valves are meant to be completely shut at idle (balanced), so whenever you remove ur carbs you have to balance them when refitted. It’s difficult to say what is goin on in ur carbs, but whenever I overhaul carbs I always use and aerosol can of carby cleaner and compressed air, this way I can see if there are any blocked passages in the carb. Whenever checking for leaks have the engine in a run position, if tilted up ur sure to have fuel run out the carbies. The serial number gives me model number 1060412GD which is an 89 model. As far as oil injection it probably has or had an auto blend, there would have been a tank in the boat, it’s safer to premix at 50:1 anyway.

Cheers Spanaman"
 
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