99 Johnson 175 bogging down

[Scrappy78]

Hi folks, 1999 Johnson 175 Hp bogging down (randomly) when trying to get on plane….no rhyme or reason when it occurs say during a 4 hour fishing trip…sometimes it happens after navigating the no wake zone and the first attempt to get on plane, sometimes it happens once out in the ocean several hours into a trip- but always happens maybe after 10 minutes of trolling speed or no wake zone speed

The solution has been to turn off the engine, trim it all the way up, lower it back down then she takes right off…I initially thought it would be a stuck carb float/needle.seat issue but rebuilt all 6 carbs with oem kits and still happens….then I remembered the vst also has a float in it- could that float be getting hung up? Just seems like there could only be so many potential problems if the solution is just to trim the engine all the way up then I’m good to go

Any ideas/input greatly appreciated!

 

[faztbullet]

Its a possibility as that float just controls vapor in VST to vapor pump. If sticking down (open) it cause cause VRO to run lean as same a air leakage in VST top. Before disassembly, when it acts up pump bulb hard and tap the choke (primer) and see if it picks up

 

[Scrappy78]

Its a possibility as that float just controls vapor in VST to vapor pump. If sticking down (open) it cause cause VRO to run lean as same an air leakage in VST top. Before disassembly, when it acts up pump bulb hard and tap the choke (primer) and see if it picks up

Thanks Faztbullet, I should have also mentioned that I have bypassed vro for oil and gone to 50 to 1 pre mix…and disconnected oil alarm wires….also should be mentioned that I also suspect a potential issue with the engine going in to SLOW mode…I have tried to run with the high temp gauge wires connected and disconnected, but the same issue of bogging down (sometimes but not all the time) keeps occurring..I know this engine runs hotter under 2500 rpm’s rather that 4500 but this issue has been occurring for 3 months now and I kind of feel I would have done catastrophic engine damage by now if it was indeed a high temp issue…so my primary suspects are still sticky needle/float somewhere, float in vst, faulty high temp gauge wires periodically going in to SLOW mode, or maybe a power pack wire issue….but again why would trimming the engine all the way up then restarting solve the problem?