5hp Nissan stalls in gear

[Cincy020]

I bought a 1993 Nissan about a month ago. When I bought it, I ran it in a tub and it ran great so I went ahead and bought it. When I got it on my boat and put the boat in, the motor ran great, and still does, in neutral. However, the motor wants to stall when ran at higher speeds in forward. First three times out I was able to get out and back to the dock running at about half power. This weekend, ran great for about 30 minutes then couldn't get the motor to stay running at low power in gear. Still runs great in neutral. I am trying to trouble shoot without taking to the shop or tearing apart so I can make it out for Memorial Day weekend. All marinas I spoke to say it sounded like a carb/fuel issue. Did some work and here is what I found and am going to correct:

1) Emptied fuel out of the tank and had 5%-10% water in the fuel. Completely emptied the tank and left open for a while to let any remaining gas in tank evaporate.
2) Checked the spark plug- the plug was loose (I was able to twist out with my fingers) and the spark area was pretty gunked up. Bought and will put in new plug
3) Upon the marinas recomendation, purchased Quickleen to run through the engine. Planned on running this throught to clean the carb before putting my mixed fuel back in.

Really want to get out next week but marinas cant get in to repair the carb. Do these steps sound logical in fixing the problem? Trying to determine if I should gamble with the motor and likely take it in to get the carb rebuilt when I can have quicker turn-around.

Thanks for the help.

 

[Picflight]

It sounds like a fuel supply problem. Trace all the fuel lines, look for damage, change filters and plugs. Add or spray carburetor cleaner to clean the jets.

Post pictures and model of engine. Report back when running with 100% efficiency.

 

[kloudie1]

Since you found liquid water in the tank, there is still some in the carburetor bowl.. and it has most likely gummed up things.. carefully remove the float bowl and, using some pressurized carburetor cleaner (available at Wal Mart or an auto parts store) clean out the bowl and spray some into the main jet, usually in the center of the bowl.. May fix it or may not without a complete rebuild/cleaning of the carburetor.. find some ethanol free gasoline and be very diligent about the oil mix into the gasoline..It sounds like the high speed section of the carb is fouled up..
Tank is built into the engine cowl, right?

 

[JK_Boston_Catalina310]

Is this a 2-stroke or a 4-stroke?

First, save your money on the Quickclean. There is no easy fix for the ethanol related problems in outboards.

Next, clean the carburetor. Take is off of the engine and disassemble it to clean it thoroughly. Use some carburetor cleaner and a small brush. You will likely see brown shellac looking stuff on the inside of the carburetor bowl. That is the ethanol that has separated from the fuel and built up over time. I also use a torch tip cleaner to get all of the jets nice and clean.

If you need help figuring out how to take a carburetor apart here is a good reference book for working and troubleshooting outboards. Lots of pictures and diagrams.

Change the onboard fuel filter and check all of the fuel lines. The filter will look like this:

If you see black specs in the fuel filter change your line from the tank to the engine. For a 1993 engine if the line is original it is not compatible with ethanol. It is breaking down and causes clogging in the fuel filter. Also check that there are hose clamps or bands (factory made connections will have metal bands) on the fuel line. You might have air getting into the system at higher RPMs at those locations. For the onboard fuel lines, Nissan (or rather Tohatsu because they actually built the motor) used the wire hose clamps. They work fine if they are in good shape. You may find a bent one, replace it. Any time a fuel line goes onto a hose barb you should have some kind of hose clamp. If you don't it can let air in.

Lastly, use an ethanol treatment in your fuel tank. Ethanol and water cause phase separation and it can be very problematic to deal with. Search this forum for a poster named "Thinwater". He is associated with Practical Sailor and has posted here before about their findings on which ethanol treatments work best. I know he doesn't recommend the brand I currently use so I won't give a recommendation (I will review his info and try a different brand after my current bottle is gone).

Also, if you engine is a 4-stroke. What does the oil look and smell like? If you stored it on the wrong side it could have gasoline in the crankcase. Among issues with less protection for metal ware this can be an issue with the carburetor. The carburetor will be connected to the crankcase breather. If you have case in the crankcase the oil/gasoline mixture is thin enough to get sucked into the carburetor but the oil makes it difficult on the combustion. So that could be another cause of the stalling out at higher RPMs.

Good luck and fair winds,

Jesse

 

[Cincy020]

Thanks everyone for the quick reply. It is a 2 stroke with the internal tank. Currently no fuel filter and the clams holding the hose on the barbs were very loose. I'll replace the fuel line and put in a filter to help with that issue.

I'm just worried about taking the carb because I don't want to mess it up. Looks easy to take off, how worried should I be? Also, how to you remember where to set/how to set the throttle linkage when you reassemble?

 

[justsomeguy]

snip- Also, how to you remember where to set/how to set the throttle linkage when you reassemble?

You could take photos, I would think.

 

[Benny17441]

Yes, sounds like gummed up fuel in the carburetor. Disassemble and soak all parts in a cleaning solution. Use compressed air to clear all passages an then reassemble and install. These carbs are quite simple, just pay attention to what you take off from where and work in a place where you are not likely to drop and loose any parts.

 

[Cincy020]

Okay, so I have the carb disassembled and soaking right now. I used spray carb cleaner on the whole thing and soaked in sea foam. Plan on doing it, blowing it out, and repeating before putting back on. I wasn't able to get the jet out, so I left it but is completely soaked and blew carb cleaner through it. To blow it out, can I use the compressed air like you would use for office equipment or use an air compressor?

 

[Picflight]

Any pressurized air should do, I use the office stuff cans often.

 

[John23883]

I had the same problem with my 9.8. Rebuilt the carb and no change. I replaced one of the spark plugs (only had one spare) and now it works fine. Turns out the spark plug had a crack in it that was almost invisible.