nissan poor coolant flow

[schoonerdog]

my nissan had zero coolant flow, dropped the lower and replaced the impeller, but the old impeller looked just fine. This is what happened last year but there were other issues with it not idling properly so I took it to a service shop to get both taken care of. Over the past few years the stream would start off ok, then rapidly diminish. The service shop mentioned lots of salt build up. I've had this outboard in a salt water environment for 9 years, and even though I flush it at the end of the season, I've had yamaha 4 stroke outboards get to the point where they couldn't be brought back because of corrosion in the small coolant passages (they were about 10 or 11 years with lots of salt water use). Any advice to trying to rescue it? Try pouring through white vinegar?

 

[TOHATSU GURU]

Re: nissan poor coolant flow

Vinegar will disolve the scale build up, but you need to find out where the cooling system has the problem. It might be a simple case of someone just replacing the impeller rather than using a kit....The liner and wearplate may be worn out.

 

[schoonerdog]

Re: nissan poor coolant flow

Interesting you mention that, I went to the service shop and specifically asked for a impeller kit and they said you just needed the impeller. Figures. Anyway, I ended up flushing it with a flushing attachment for an hour with a hose and then had an adequate flow but not great, I then stuck a bit of a small wire into the coolant outflow hole on the power head and the flow instantly doubled. Must have been something caught right at the exit.

I got to say though that putting that lower drive on was the most insanely difficult thing. I've worked with a friend who had a johnson because I wanted someone who'd worked with their outdrive and their johnson took about 10 minutes, we were trying to line up the shaft and shifter for two hours. When we called the service shop and asked if there was any trick to it they simply laughed and then said "you've just got to have patience".

Just out of curiousity, for anyone whose worked on different outboards what are some of the easier ones to work on? Also, do two strokes handle things like water and grit in the fuel better than four strokes?

Vinegar will disolve the scale build up, but you need to find out where the cooling system has the problem. It might be a simple case of someone just replacing the impeller rather than using a kit....The liner and wearplate may be worn out.