NS8B 8HP Won't Start...Please Help.

[Nissan Newbie]

I have read almost every thread on this forum and can't find my question. Correct me if I'm wrong of course. I am new to this motor and outboards in general. The only way it will start is with starter fluid (I know its very bad for the motor) will run for a second and die. When I got the motor it was completly seized. I soaked the carb and put penetrating oil in the cylinders. Everything was freed up. I have checked the float needle (cleaned and moves fine), replaced the spark plugs, fuel filter, engine side gas line connector, fuel line with primer bulb and fuel tank. I filled my new tank with 89octane with a ratio of 50:1. I pulled the bottom spark plug and hooked up a compression gauge (60) and repeated on the top cylinder (49). Before you tear me apart, I don't have any mechanical exp. I just want to take my boy fishing. Thanks in advance! Any help would be great.

 

[pvanv]

Re: NS8B 8HP Won't Start...Please Help.

Your compression is low, but the biggest thing is that you probably aren't delivering fuel. Just because fuel gets into the carb bowl does not mean that the carb is mixing it in with the airflow. Did you completely disassemble the carb (removing the jets and nozzle), and do a 4-hour soak in real carb dip? If not, that must be done. But... Was the motor ever submerged... or was it seized because it was stored in a humid environment? If so, you may have corrosion in the carb passages, which means you will need a replacement 3B2032001M CARBURETOR ***'Y $173.50. Are you sure you want to spend this time and money on a likely worn-out motor? Do you have the factory service manual? If you are still bent on getting this motor working, you should consider one.

 

[Nissan Newbie]

Re: NS8B 8HP Won't Start...Please Help.

I may have done the compression test wrong...after reading the FAQ on how to do it. I had the other plug in when I did it and the fuel line hooked up. I also only gave it one pull then released the pressure and did it again. I did soak all the components to the carb for about a week (thats how we freed it up). I'm not sure if it was ever submerged or not it was in a storage unit when we got it. I dont think fuel is getting to the float bowl... I would prime the bulb and try to start for a good 10 mins and then prime again and when I unscrewed the drain screw on the bowl it was empty... Could my fuel pump be the issue? I Would like to spend the time to get it running for sure. Thanks again.

 

[Nissan Newbie]

Re: NS8B 8HP Won't Start...Please Help.

Ok I did another cmpression test per the FAQ thread on how to do them. On the top cylinder it was 90 and the bottom was 60. Do you think the motor is too far gone? Thanks again.

 

[pvanv]

Re: NS8B 8HP Won't Start...Please Help.

You may or may not have a pile of junk on your hands. Hard to say whether you are getting accurate compression figures. Typically we say that anything over 10% variance between cylinders means rebuild time. But you definitely would need to either go through the carb or replace it. Start with the Factory service manual, Part# 003-21035-1, $44.17, available from any dealer, including me. Disassemble and inspect the carb -- or have someone who is familiar with small motor carbs help you with that. A carb kit is available, if yours is good enough to rebuild, Part# 369871221M $38.62. If you get some semblance of air/fuel mix flowing, you probably at least get the motor to fire. Then you can decide whether to spend any more time or money on it.

 

[Nissan Newbie]

Re: NS8B 8HP Won't Start...Please Help.

Great will do! Thanks again. I tor apart the carb last night and it is and will be soaking in carb cleaner for the next 3 days. I also noticed a few gas lines on the side of the motor (not attached to the carb) were shot so I replaced those. One more question...the cylinder were the float valve goes in an out does that come out? I think thats were my block is because nothing is moving through there like the other cylinders are.

 

[Nissan Newbie]

Re: NS8B 8HP Won't Start...Please Help.

Anybody?

 

[Nissan Newbie]

Re: NS8B 8HP Won't Start...Please Help.

Thanks for all the help I got it running today!