Re: BF8A New Head Gasket - No Pee
I didn't think the problem was the impeller since it peed pretty good prior to replacing the head gasket. I assumed that I must have done something wrong... maybe something common enough that someone else would have an idea or suggestion.
Since no one had any ideas, I figured that It wouldn't hurt to replace the impeller. I've only owned the motor for about 6 months. I was told that it was used exclusively as a back up and never needed, so it was supposed to have very, very low hours... but who really knows anyway.
There are 5 bolts on the gear case holding it to the leg. Damn broke 2 bolts getting it off... then broke my easy-out after getting a nice clean hole drilled. Time for a pro on those two.
The gear case came off with a few raps from a rubber mallet. Prior to those 'raps' I had to pull a cotter pin that's in the linkage pin at the top of the shifter shaft inside the cowl at the top front. It's kind of hard to see and get to but it helps if you put it in forward as it lifts it up some.
With that pin out the shift shaft will pull down about a foot which is enough room to replace the impeller. If you need to pull the gear case all the way off, you need to remove the fitting at the top of that shaft. I'm not sure the easiest way to do that, since I didn't need to and didn't do it. Probably while it's still up in the engine, I'd guess.
The pump housing and seperate auxilary housing are held down by 6 bolts. Fortunately these came out fairly easily. All 6 have metal... 'tubes' they go through and washers. Becareful as these can fall into the forward part of the gear case and become very difficult to remove (ask me how I know).
There is a metal plate under the pump and auxilary bodies with a gasket on either side. I used a flat razor to scrape the old gaskets off. They were if ok shape, no signs of leakage. Inspecting the impeller... I found the problem. The only really surprising thing... is that it pumped water at all before the head gasket job. 6 of the 8 fins were cracked, torn or missing. The remaining 2 had very little spring.
Under the pump housing and metal plate is the gear case oil seal. This was a real pain to get out. Normally with oil seals, you can punch through and pry out. But, that's a bit scarry when you aren't sure what's underneith. I tried with a small punch... but broke the punch. I ended up folding the side down and splitting it with a cold chissel. This gave me a lip to grab with needle nose plyers and allowed me to pull it out.
I cleaned out the seal seat and carefully tapped the new one in place with a dowel and rubber mallet.
The impeller went in with a twist to pre-load it in the correct direction. The metal tubes were a bit of a pain as they didn't want to go in from the top and wanted to fall out when I put them in from the bottom. Finally managed to hold them in while I got everything lined up and the bolts back in.
Fortunately, the two bolts that broke were the middle ones. That left the back center and the two front. Enough holding power for me to confirm that the impeller was the only problem. I got a flash light to confirm I had the water tube in place and had to spin the prop slightly to lineup the drive shaft.
I got the 3 unbroken bolts back in and the linkage pin and cotter pin went in without too much fuss. That could have been bad though, as dropping either would have put them in a very inaccessable hole.
It took some effort to get it started, it'd only run about 2 minutes since I replaced the head gasket a couple weeks ago and I hadn't adjusted the carb yet. After several pulls, I pulled the top plug and found it to be totally dry, so I increased the throttle and choke and got it started.
Sure enough right off it had a very strong tell tale stream.
I spent about an hour adjusting the carb to get it to idle low, these motors often don't like to do that. I had to pull the low idle jet and clean that out, adjust the throttle cable and linkage and set the idle stop and idle air adjustments. In the end it would start every time with a half hearted pull on the rope and idle nice and slow.
Just one more example that shows... you should replace the impeller every other year whether it looks like it needs it or not.
