Nissan 8 HP 4 stroke possible cooling problem

[Hightaxes]

:blue: Hello All. I have a 2010 Nissan 8 HP 4 stroke with approximately 60 hours. I've used it all summer without any problems until today. Half way across the lake at a medium pace, the engine started running rough, then started steaming. I noticed that it had a very strong stream of water and the steam was coming from the steam port. Feeling the water it felt warm and I could allow it to pour over my fingers. I slowed down and stopped and the engine died. The only way it would restart was with the choke fully on. Push the choke back in and it would die and there was no way to throttle up. I ended up rowing back to the launch. Once there I removed the cover and everything was dry. Checked the dipstick and the oil was golden brown. Right now the engine is at the shop. My question is...can the impeller be out and still show a steady stream thats warm or could it be a blown headgasket. It's no longer under warranty and is a $2100.00 motor, so I'm a bit concerned.

Thanks

Jim
Spanaway, Washington

 

[pvanv]

Re: Nissan 8 HP 4 stroke possible cooling problem

What was the oil level?

 

[Hightaxes]

Re: Nissan 8 HP 4 stroke possible cooling problem

What was the oil level?

The oil level was full, golden brown in color.

 

[Hightaxes]

Re: Nissan 8 HP 4 stroke possible cooling problem

I was told that it appears that I may have a carburator problem and that the main jet is clogged. If this jet is clogged and I'm using the choke, the engine will run very rich causing it to run hotter than normal and that would account for the steam. If this is true, then I have a full 3 gallons of gasoline to dump that I just got.

 

[smashed]

Re: Nissan 8 HP 4 stroke possible cooling problem

Why can't you use the gasoline once you clean the carb?

 

[Sea Rider]

Re: Nissan 8 HP 4 stroke possible cooling problem

Yep,with a mesh filter, filter tank's fuel and put back in...

Happy Boating

 

[pvanv]

Re: Nissan 8 HP 4 stroke possible cooling problem

I was told that it appears that I may have a carburator problem and that the main jet is clogged. If this jet is clogged and I'm using the choke, the engine will run very rich causing it to run hotter than normal and that would account for the steam. If this is true, then I have a full 3 gallons of gasoline to dump that I just got.

Rubbish. If you run too rich, the motor will run too cold. Period. It will also foul plugs fast, and build up carbon in the chambers fast.

If the oil is too full, even a drop, you will experience high crankcase pressures, and that could be your problem.

If the carb is varnished, the problem typically shows itself in idle and slow speeds, and possibly tipping-in from idle. Now then, if a chunk of crud got through the filter, and got sucked into the main jet, that would affect everything, because the main jet is also the supply for the low-speed jet. So your advisor is mistaken, to put it lightly.

What is the "steam port"? If you mean the telltale stream, that should always be flowing, and should be warm. If the idle relief port was streaming a lot of water, that's odd, and could indicate some zebra mussels had taken up home in the through-prop exhaust.

If you have a strong telltale, the pump is pumping, so the impeller would not be the cause.

What has your dealer come up with so far?