1988 johnson 48 hp SPL missing - update

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earl60446

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I have a 1988 johnson 48 hp SPL with remote, been running good for a couple years (since I bought it). Went on vac recently and it ran good the first day, then it refused to run at high throttle, missing a lot. I thought it might be the fuel bulb, replaced it, no luck. Took off the fuel pump, that looks ok and Pappy said once ( I think) that a fuel pump either works or don't, no in between. I used the motor 4 days running around at maybe 1/3 throttle. I noticed a water leak at the bottom of the head jacket, need to fix that, could it cause the motor to throttle down, even when first starting in morning. I think it has the SLOW option. Tell tale is "peeing" strong. Tried new plugs too. Now I'm home, looked at coils, 0 ohms from grd to pri and 254 ohms from grd to sec on both. Spark at plugs look good (strong and blue). I did not hear any alarms. Should I tear into the carbs or what say you? TINBOAT experts.
Tim
 
Not sure on specifics of your motor but I once had a drip caused by water jacket gasket and after running it for a bit enough water managed to moisten the end of my plug wire and would cause one of the cylinders to misfire. This was on a 25hp merc and only thing I could figure was vibrations from high rpm and boat hitting waves caused just enough water to splash up onto the boot of my plug wire on the bottom cylinder. Could also be water in fuel or carb related but running fine one day but not the next usually isnt one of those.
 
Sounds like a main jet in a carb is clogged. Take it out again and while running full throttle push in and hold the choke on. If it takes off and runs normal you know you have a fuel problem. I've owned 3 1988 48's over the years. Great motors but you need to run some Seafoam or other good cleaner through the fuel system fairly often to keep them running properly, especially if running alcohol blended gas.
 
Well, I tore into it today, found that one nut on top carb holding it to the intake manifold was loose, took it off anyway. Cleaned it all up (was clean), checked holes, float, etc., blew it out with air. Took off the bottom carb, found a piece of plastic in jet that is opposite drain screw on bowl. Removed that, blew it all out, etc.. Only other carb work I have ever done was mess with my mower carb (which now works). All gaskets in good shape. Put all the carb stuff back on. Removed the cylinder head water jacket cover, found 2 bolts on bottom missing, needs new gasket and replacing thermostat / seat since I'm in there. This is stuff you get when buying 26 year old boat / motor sometimes but it was ok for last 2 years. New parts on order. Thanks for the help guys and BTW, my water leak was way more than drip LOL.
Tim
 
Well I took my boat out today for the first time since doing the work on it. That motor is running like the proverbial raped ape! Yippee, I was very happy, never missed a beat, I think it ran better than I have ever had it run before. Plus I caught 1 little striper, told my buddy he owed me $10, $5 for first fish and $5 for biggest fish, he caught nothing. :mrgreen:

Also did a good deed, towed in a guy and his wife with a broken motor. He was in a bad way, said he had hodgkins lymphoma and leukemia plus experiencing kidney failure, he was just trying to enjoy the day fishing and his motor went kaput. Told him to hang in there, he said "Don't want to", pretty sad.

Tim
 
[url=https://www.tinboats.net/forum/viewtopic.php?p=357249#p357249 said:
earl60446 » Yesterday, 18:20[/url]"]Well I took my boat out today for the first time since doing the work on it. That motor is running like the proverbial raped ape! Yippee, I was very happy, never missed a beat, I think it ran better than I have ever had it run before. Plus I caught 1 little striper, told my buddy he owed me $10, $5 for first fish and $5 for biggest fish, he caught nothing. :mrgreen:

Also did a good deed, towed in a guy and his wife with a broken motor. He was in a bad way, said he had hodgkins lymphoma and leukemia plus experiencing kidney failure, he was just trying to enjoy the day fishing and his motor went kaput. Told him to hang in there, he said "Don't want to", pretty sad.

Tim
=D> =D> =D> =D> =D> =D> on both counts!
 

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