The Carburetor Rebuild Adventure

This is for you Do-it-Yourself boat motor mechanics out there and I know there are a few of you, or at least I hope I'm not the last. As you may know from my earlier articles I have a new boat and it was having some issues.  These issues were a result of it sitting for almost 2 years with the new gas we have to buy with up to 10% ethanol added sitting in her carburetors.  If you have done any reading on this new ethanol gas you will know it can cause some big problems if the gas is not used quickly.  Point is the gas goes bad and if left in carburetors once it goes bad it will form a varnish that will clog up all the jets and ports.

My motor is a 1990 Yamaha 150 Pro-V and from all the research I've done on this engine I've found they are pretty bullet proof if well taken care of by the owner.  That the previous owner had taken good care of this engine was very evident in its appearance.  In fact when I asked to look at the boat

he even drained the old gas and put some fresh in the tank.  When we tested it on the hose she fired right up and idled smooth.  So I ended up buying the boat only to find out she wouldn't get on plane and wanted to die if you pushed her past 2200RPMs under load.  So my research began into troubleshooting this problem.  I did all the easy things first like changing the filters, fuel pumps and spark plugs.  This didn't help so it was time to dig in and rebuild the carbs.  This sound like it might be a big job, but it really isn't so bad at all for us Do-it-Yourself mechanics.  The fact is this isn't my first rodeo on rebuilding carbs as that started many years ago when I was racing stock cars. It continued on as I worked on all of my vehicles, well up until the time that you had to own a NASA computer to figure them out.  I also did all the maintenance and repairs on every boat motor I've ever owned including rebuilding the Johnson 88spl on my Cajun Bass Boat I still own. By the way my old Cajun is for sale and would make someone a great bass boat.

OK enough with my history of being a Do-it-Yourself mechanics and on with the actual rebuilding of the carburetors.  I started at about 7:00 AM Friday morning and had the carbs off and the first one disassembled by 8:00 AM.   I had taken out all the brass jets and other screws from the main body and removed the bowl, floats and valve assembly as well as all the plastic parts.  I then submersed themain body and bowl in some Berryman's Chem-Dip.   The Berryman's Chem-Dip come is what looks like a paint can and it has the solvent in it as well as a dip basket.  You just place what you want to clean in the basket and dip it in.   The directions tell you how long, but for what I was doing it would be 2 hours.   Now I must warn you there are two versions of the Chem-Dip, one is a California version that is also sold in some other states as well as on line, then there is the original version.  From what I understand the California version doesn't work very well, but I'm in Texas so I was able to easily find the original. I also have to warn you not to put any gaskets or plastic parts in the Chem-Dip as it will eat them. The original version does work awesome for cleaning carbs!!!  Now to clean all the jets and screws

that I removed I used Berryman's B-12 Chemtool.  I put them all in a glass jar with a screw-on lid then sprayed them down with theB-12 until they were all covered.   Then I placed the lid on the jar and from time to time over an hour I'd shake and swirl them around in the jar.  After an hour I carefully removed them from the jar and then took a copper wire brush and a small piece of copper wire to clean them out good.  Let me tell you some of these jets were completely clogged from that ethanol gas.  It took me some time to get them all perfectly cleaned. This process was to clean some and let them soak some.  Once I was happy with how they looked I blew them all out with my air compressor air gun.  I made sure that air could easily flow from all the jets.  I then started to dissemble the second carb.  When finished I put the second set of jets in the same jar with the B-12.  When this was finished it was time to get the main body and bowl out of the Chem-Dip. I removed them then placed them in a water bath.  Water is used to disperse and neutralize the Chem-Dip.  I then placed the second main body and bowl in the basket and lowered them into the Chem-Dip.
 
At this point I took a short break to go check to see if the mail had come and if my if my Carburetor Rebuild Kit was here.  I had ordered and aftermarket kit made by Sierra because I could get it here in time for Friday or so I hoped and also because it was about $40.00 cheaper than the OEM Yamaha Kit.  When I got out to the mailbox I found my kit inside and was very happy.  I took it in the shop and made sure it was the right 18-7759 part number and that all gaskets and parts were in the package.  Once I knew the kit was right I started putting the first carb back together.  Again I took my air compressor and air gun and completely blew out

both the main body and bowl.  I made sure that air could easily pass through all the ports on them before I started to reassemble the carb.  Once the first carb was back together it looked almost like a new carburetor. Then over the next few hours I completed the process on the second and third carbs.  Everything was going smooth or maybe it was too smooth so to speak.   I had the carbs back on the motor and hooked up by my planned 3:00PM and she was ready for a test.  When I was pumping up the bubble to push gas into the carbs it seemed to get hard faster than normal but I didn't pay much attention to it until after the motor wouldn't start.  It was then that I realized the gas wasn't flowing into the carbs.  I checked a few things and tried to pump the bubble some more but nothing.  I pulled one of the drain screws to be sure I wasn’t getting any gas and it was bone dry.  By this time it was after 4:00PM and time for me to get ready to take my wonderful wife out for our weekly "Date Night".  The motor and carbs would have to wait until Saturday morning which meant I'd likely not get any fishing in this weekend as Sunday was Mother's Day.

Saturday morning found me up at my normal 5:30 in the morning.  I got the coffee on and waited for it to get light enough to start work, but that was over an hour away.   I had finished 2/3 a pot of coffee by the time 6:45 rolled around and I could get to work.  I took all the carbs off the motor and into the shop to see if I could find out what was wrong.  I knew it had to be something with the floats and shutoff valves but what.  So I pulled the bowls off and did some adjusting to what I thought was right and put them back on the bodies.  Only way of knowing if this was the fix was to put the carbs back on the motor.   I had that finished by 8:00ish but my wife was still asleep.  Now most of us smart married men know that a happy wife is a happy life and so I didn't try to start the motor yet.  It was just an extended coffee break.  In fact it was going to be one of those two pot mornings as I got the second going.

My wife crawled out of bed about 8:30 and with the excitement of getting the boat going good plus all the coffee I had drink, I was wired.  I warned the wife what I was going to do and headed out the door.  I started by pumping up the bubble again and this time I could tell gas was flowing.   However this time is seemed to take longer than normal but I counted that to no gas being in the carbs at all.  When I started to smell gas though I looked and saw it pouring out of the front of the carbs.   So I had gone from the floats and valves not letting gas in carbs to them not stopping the gas once the bowls were full.  It was back to the drawing board or in this case work bench.  I took the carbs back off and headed back into the shop for more troubleshooting.  This time when I tried to pull the bowl off the first carb I found the float was stuck and the bowl wouldn't come off.  In fact I ended up having to break the one float to get the bowl off.  I also had difficulty removing the bowl on the other carbs as well.  What this told me was the floats were bigger than the original floats.  I was a little mad as there was no instructions in the kit that told me the floats might need to be sized and after paying $120.00 for the kit one would think all the parts would be right.   Well I was lucky as all the original floats were in good shape besides being pretty dirty.  I cleaned them up and put them in the carbs.

I got the carbs put back together with the old floats and back on the motor.  I pumped up the bubble and everything seemed to work as it should.  Once the bubble became tight, I turned on the water to the hose and then tried to start the engine.  To my absolute pleasure the engine purred to life at the first bump of the key.  It sounded really good and would rev up, but of course that was with no load so a water test was in order.  I knew I wasn't going to get a chance to put her in the water today as we were now babysitting our granddaughter.  Also my wife had plans she needed to do in the afternoon and so there would be no water test for the new boat.   However my wonderful wife knew I was disappointed and came up with the solution that I loved.   She asked for me to take her on a morning boat ride for Mother's day.  Hey what better way to test my carb job than with the woman I love, right?  

Sunday morning found us launching the boat about 10:00AM on Dickinson Bayou.  I could tell the motor had more power as I backed her off the trailer.  I watched with much anticipation as my wife parked the truck and trailer then headed to the dock.  She climbed aboard and secured her PFD in place before taking a seat.  I eased the boat towards the “No Wake” buoy as the excitement about what would happen started to rise within me.  I glanced at my wife and could tell she didn’t know what to expect either.  I was somewhat concerned as we did have 20mph winds gusting to 30mph out of the southeast and with Dickinson Bayou pretty much running east to west this meant a crossing wind.  I wasn’t concerned about waves as no matter how much wind we have the bayous really never get rough.  I was concerned with this wind getting under the bow once we were on plane.  As we pass out of the “No Wake” zone I stepped down on the “Hot Foot” and my girl jumped forward way quicker than I had expected.   She was on plane in a second and moving fast.  I didn’t get her wide open at this point as we need to cross under the railroad bridge first.  Once we clear the railroad bridge there is a pretty good straight and wide stretch that is fairly protected from the wind.  When we got to this point I opened her up and she responded by bringing tears to our eyes and the skin on our faces started to flap.  She quickly ran up to the 5600RPMs she was supposed to get with the new prop and was picking up speed fast.  At about this time the cross wind came into play and started to make her get a little squirrely so I backed off some.  Needless to say I was very happy!!!  We did spend the next hour riding up and down the bayou to my wife’s delight and mine as well.

Now as far as the Sierra Rebuild Kit, I’ll never get one again unless a Yamaha OEM kit is not available.  I don’t believe that you should have to make modifications to parts after spending that much money and if modification are necessary Sierra should have pointed that out in their sales description and also in instructions contained in the kit.   The Berryman products are top notch in my opinion but be careful not to get the California version of the Chem-Dip and you should be very happy as well.

Until next time, Tight Lines and Take a Kid Fishing!!!

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