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1991 28 HP Johnson bogging down and feels hot!

S

Stephen Ebner

New member
I have a 1991 Johnson 28 HP that sat for about 5 years. I put new gas with seafoam and new gas line on. Changed lower oil. Runs good on idle. When I give it some throttle then it starts to bog down. I back off and it starts to run fine again. I checked the ball and its hard. It spits out water like it should. I guess I'm just looking for help as to what I need to do. I don't want to take it in unless I absolutely have to. Thanks in advance.
 
Do I just push the key in when I have the throttle pushed about when its ready to start bogging down? Would a bad carb make the shaft of the engine by the exhaust get hot?
 
I did push the key in and choked it didn't seem to do anything. I bought some carb cleaner and sprayed it in it when it was running and reved it up a little. It started smoking and would seem to be miss firing or running off one cylinder. I checked my spark plugs and they were wet and very black. So tomorrow I will get new plugs and see if that works. Would you check or do anything else or maybe think of something I'm missing?
 
Sounds like it wants to open up then it chokes down then back up then down. A lot of smoke came from the exhaust when I sprayed the carb cleaner in it and reved it.
 
First check the compression on it. Then squirt some fuel in the carb throat and see what happens. If that doesn't do it, pull one plug wire off at a time and see if it's running on both cylinders.
 
The compression on both were about 105lbs I did pull the wires off one at a time and it is running on both cylinders. Still no luck. Starts and when I give it gas still boggs down and dies. Don't know what to do anymore. I did look at the drawing for the carb I don't know if I should take anything off and clean it. People are saying the jets but I only see the slow speed adjust needle. I also noticed when I was doing the compression test, by the top oil screw for the lower unit there is a water drain hole and it seemed to leak oil from there.
 
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Here are some pictures one of the carb I have in it. The other is where oil was coming out of. I don't know much on outboard engines so I do appreciate all the knowledge and help you have given me. Thank you!
 
Stephen Ebner said:
View attachment 11267View attachment 11268
Here are some pictures one of the carb I have in it. The other is where oil was coming out of. I don't know much on outboard engines so I do appreciate all the knowledge and help you have given me. Thank you!
Click to expand...

You should get a book on this engine - they are available here on this site too. It will outline all the basic stuff, including rebuilding carbs, which is probably in order if the engine sat for 5 years. Typically "bogging" when you try to accelerate is a lack of fuel caused by clogged jets in the carb.

It sounds like you checked spark as Boobie outlined and compression is OK so most likely you are down to the simple/common thing.

I don't know what that drain hole is exactly but 2 stroke outboards almost always are dripping some sort of black oily goop from someplace around the lower unit. Anything the exhaust touches gets covered in that stuff, add some water, and you have those drips. Usually the cooling water and exhaust both get dumped together someplace prior to exiting the engine resulting in sludge.. Since 2-strokes do not have actual engine oil (they just burn it) for the most part dripping oil, smoke, etc.. etc.. is of no concern.

Now some odd problem might cause more or less such garbage but it's not usually of any trouble-shooting value or worry so I'd ignore it unless somebody points out it's an exception. Gear lube you do not want to be leaking but from your description it doesn't sound like gear lube. With an oil injection system you don't want to see a bunch of leaks there either but similarly it would be clean oil like the stuff you dump in.

Jon
 
Thanks for the advice and knowledge Jon! I will try to see if I can get the top half off of the carb to see if I can get to the jets which I'm sure that's where they are? It seems pretty simple to do I just don't want to mess anything up and damage something. I will see at getting that book for the engine as well.
 
Hi Stephen,

To rebuild a carb you remove the whole thing, typically then removing the bowl, float, needle, seat, jets, sometimes also welsh plugs. The rest typically stays together (ie butterfly parts do not usually need to come apart).

Parts that are 100% metal you can spray out with carb cleaner, parts that are not 100% metal you cannot use carb cleaner (I use generic WD40 to spray out plastic parts). Compressed air, even just a can of computer duster, is good for drying and blowing out crevices. 100% of any gunk needs to go and it needs to be clean, ie no specs of anything in there.

Once it's clean you put it back together (using a carb rebuild kit for new gaskets, new float/needle/seat), setting the carb float to the correct height by the book. It is really very easy but you do need to pay attention and be careful. The only tools required that might be uncommon is a variety of flat head screw drivers, since it often takes just the right size to remove jets.

Jon
 
Jon,

Would you buy a carb kit from here or would you go to a marine shop? What do you think would be the best option? I would like to get the boat up and running as soon as possible so I can start fishing.

Thanks again
Stephen
 
Stephen Ebner said:
Jon,

Would you buy a carb kit from here or would you go to a marine shop? What do you think would be the best option? I would like to get the boat up and running as soon as possible so I can start fishing.

Thanks again
Stephen
Click to expand...

The fastest thing is obviously just to buy one locally - you aren't talking about a whole lot of $$ ($20 to $50) and it's best to get one from the manufacturer anyway.

Usually this part will be in stock anywhere that does some volume.

Jon
 
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