Trying to figure out 25 or 35 hp Johnson

flintdiver · Aug 18, 2011

Ok so 1st off I bought this engine and was told it was a 25hp or 35.The cowling sticker was torn off.On the sticker on the side of mounting bracket it says mfg part# aml35d So any help on that would be great. Now ,the main issue I'm having is the engine cranks and idles perfect.When I give it a little gas ,its fine.When I twist on it to plane, it sometimes will jump on plane then bog till it nearly quits or bog as soon as the throttle is accelerated.Now when it does this I can adjust my palm over the carb opening a certain way,and it runs full throttle fine.But I have to adjust my hand perfect.What is going on here?The carb has been gone thru and cleaned thoroughly.I have new fuel in the tank. ????Please help!!! thank you

fireman57 · Aug 18, 2011

Re: Trying to figure out 25 or 35 hp Johnson

You still have a fuel starvation issue. You are essentially choking it with your hand over the carb. You have a high speed jet that is clogged. You really need to soak it overnight and blow everything out well with compressed air. I'm betting that it has a gold hood on it. the aml were referred to as military motors. I am guessing that it is a 1995 or 1996.

flintdiver · Aug 18, 2011

Re: Trying to figure out 25 or 35 hp Johnson

Thanks Fireman, what about the Hp? any idea there? So this could not possibly be a fuel pump issue? just checking....? thank you

fireman57 · Aug 18, 2011

Re: Trying to figure out 25 or 35 hp Johnson

It is a 35. I doubt it is a fuel pump issue because it just delivers fuel. It does not control the air mix. You did that by hand. If you want to check your fuel pump all you do is when it bogs squeeze your primer bulb a few times. This overrides it and forces fuel into the carb basically bypassing the fuel pump.

flintdiver · Aug 18, 2011

Re: Trying to figure out 25 or 35 hp Johnson

Ok, yes I have hit the primer and it still does this.So I will soak it.Would you recommend carb and choke cleaner sprayed into a jar or buying some industrial type carb cleaner?

fireman57 · Aug 18, 2011

Re: Trying to figure out 25 or 35 hp Johnson

get quart of good carb cleaner and put it in a glass jar and soak it. Make sure you get all the passages clean, if you have to take a very fine strand of wire and run it through them. You also might put an inline filter after your primer bulb to keep stuff from getting in there.

flintdiver · Aug 18, 2011

Re: Trying to figure out 25 or 35 hp Johnson

will do. As for your knowledge,I have another question if I may? To the right of the choke pull there is a pull labeled "drain". The lines off the drain block are plugged.Is this ok? I have a fuel supply line and a small line leading from the choke to the top of the carb now thats it.What is the function of this "drain" ?? Thank you so much!!

fireman57 · Aug 19, 2011

Re: Trying to figure out 25 or 35 hp Johnson

You know that is a good question. I'll have to research that! By the way is seems you are the winner of my 2500th post and I don't know the answer. Yet! Edit: That is nothing but a drain. It is the lower housing drain. I guess it lets water/spilled fuel out of the housing so it doesn't sit in there.

flintdiver · Aug 19, 2011

Re: Trying to figure out 25 or 35 hp Johnson

lol, thank you for the edit! I'll update after I try the carb soak.Thank you,you have been a tremendous help...

kfa4303 · Aug 19, 2011

Re: Trying to figure out 25 or 35 hp Johnson

Hi flintdrive. Once you got the carb nice and clean, this should help you get her dialed in. Good luck.

http://forums.iboats.com/showthread.php?t=167352

rico suave · Aug 19, 2011

Re: Trying to figure out 25 or 35 hp Johnson

I have the 25HP which is the same. In many cases you don't even need to remove the carburetor. Try removing the needle valve and the lower nut where the float is located and blow some compressed air through both. If it's a minor ethanol snot you can sometimes clear it up in this manner. I've gotten to the point where I keep a can of compressed air on my boat just in case.

Trying to figure out 25 or 35 hp Johnson

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