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BF50 water jacket in intake completely clogged

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Paulwroth

New member
Hello folks. I just got a 2002 pontoon boat with a BF50 on it. Starts and idles well, super smooth at low rpm. When i start increasing throttle have to go slowly or it dies. When i get it up to mid throttle feel surging. At full throttle im only getting 3000 rpm. I put new plugs in, the old ones were a darker brown than seemed normal but even. Pulled the intakes to clean the carbs (its acting like fuel issue to me) i found the water passages through the intake completely clogged with a sandy grit. Also someone must have lost the brass plug that holds the #2 jet in place and had what seemed like cork in there. So i ordered the plug, new intake gasket and anode (the anode was severely coated and had a chunk eaten away). Figured thiscwas where to start. Just wondered if the intake coolant passages was normal and how to keep it from happening again. I figure til i get these things fixed i cant troubleshoot further. Engine has 190 hours. Thanks
 
No it is not normal for the water passages to be blocked. Clean it out as best you can and remove the water jacket cover on the opposite side of the head from the intake, I am guessing that too will be clogged.If it is, clean it out thoroughly and fit new internal anodes whilst you're at it. Then remove the lower unit and the thermostat and introduce a good flow of water into the water feed pipe at the water pump side and make sure you get a nice free low with no back pressure. You may have to remove the cylinder head too if that appears clogged. I would say from your description of how it's running that it has sat for a long time and at some point had stale fuel left in it, a good thorough cleaning of the entire fuel system should fix this.
 
iang6766 said:
No it is not normal for the water passages to be blocked. Clean it out as best you can and remove the water jacket cover on the opposite side of the head from the intake, I am guessing that too will be clogged.If it is, clean it out thoroughly and fit new internal anodes whilst you're at it. Then remove the lower unit and the thermostat and introduce a good flow of water into the water feed pipe at the water pump side and make sure you get a nice free low with no back pressure. You may have to remove the cylinder head too if that appears clogged. I would say from your description of how it's running that it has sat for a long time and at some point had stale fuel left in it, a good thorough cleaning of the entire fuel system should fix this.
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Thanks for the reply. I got it from a young guy who ran it all summer. No telling how long it sat before he got it. Im surprised there werent overheating problems. Motor pees good so there must be a way the system bypasses the clogged area. Carbs were pretty clean. I didnt know there was
an access plate on the other side. Im going to order a manual today, and i did go ahead and order a new water pump with the other parts needed so ill blow everything out. Thanks
 
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