Re: Johnson 70 HP carbs
What year is your 70hp? How many carbs? Probably three right? I have never boiled carbs. I have heard that this process helps out a lot, but I have always had good luck with carb cleaner and an air compressor.
It's difficult to take a carb apart fully with the linkages attached. I can't remember how they attach to the carbs, but if you have to take linkages apart to remove them, make sure you mark the original adjustments with a black perminant marker. If they don't go back exactly like they were, the sync 'n link will be off, messing everything up.
I don't have all of the specific tools to take out the jets, but I have been successfull in the past with various screw drivers, chosing the one that fits the tightest. Be careful because they are brass and will be easily buggered up. Many times, I will take a small paper clip and a large paper clip, and use them to chase the jets, rather than remove them. Usually, If I am cleaning carbs for the first time, I will try to remove every jet. Also, the needle valves should be inspected. If there is any deformation noted to the pointed rubber end of the needle, replace both needle and seat. Remove the seat and check for varnish(this is where a paper clip comes in handy, cleaning varnish in hard to reach sopts. If there is build up of varnish in the float bowl, you can use emory cloth to clean it up. You want 0 varnish in the carb. I have also used a drill bit that fits the high speed jets, to chase them. One time, after cleaning carbs x 2, I utilized this method on the 3rd attempt, removing a huge glob of varnish. This solved my problem. If you do this, use a drill bit that just fits the jet, The idea is to chase the jet without scratching it.
If you do all of this, using carb spray and an air hose, you will have very clean carbs. The next thing you will want to do is install a fuel/water separator. This will keep junk from building up, and keep water out of your carbs. Sometimes, I will add an aditional filter in the gas line, between the tank and the engine connection.
If you do all of this, and remember to change out your filters anually, you should never have a problem. Remember, if you have black plastic clips that hold the gas line onto the tank and engine, replace them anually. They fail, creating air leaks. The brass fitting on the fuel tank will fail eventually too. Along with an extra plug, spark plugs, spare prop, you should have an extra fuel line clip and a brass tank fitting. Make sure you have all of the necessary tools.
Also, remember to run your engine out of gas if you plan to store it for more than a couple of days. I recomend doing this every time you put the boat on the trailer. God knows, we often think we will be right back on the water, then days become weeks...
Hope this helps.
