gbryant04 Posted October 20, 2015 Posted October 20, 2015 Hello BR, I am new to bass resource and just recently bought my first boat. I have a 99 Bass Tracker Pro Team 175, with a 1976 Johnson 75 horse. I have been having a slight issue with my engine that i wanted suggestions on what your ideas on a fix are... When engine is cool I have no issues and it will start and take off fine no problem. When the engine is warmed up, if I stop and then try to give it throttle, the engine will bog out and die. If you feather the throttle and get it passed a certain " point " the engine will take off fine and run with no issues. Only happens when engine is warm. From a stop to WOT it will most always bog down and die when engine is warm. -I have rebuilt all three carbs with their respective kits -Always run Seafoam through each tank of fuel -Checked that my prop was the correct size for engine (13.25x17) -Changed plugs (twice actually) -Changed Thermostat I know the engine is a bit older in years but with the way it runs once it is past that certain rpm point I am stumped on what it may be. It will take off and run great when engine is cool (Ex. first backing into water or after motor has set not running for an extended period) Any ideas for what to try next? Quote
Ski213 Posted October 21, 2015 Posted October 21, 2015 Make sure the carbs are synced correctly. Then double check it. There should be a low speed screw of some sort. If you're looking down the carb throat the head of the screw should be facing you. Make sure they're all set at the recommended number of turns out. Mine did something similar. Courtesy of advice received here I did those things and mine lined out. Plenty of other possibilities but just thought I'd throw those two out. Quote
Ski213 Posted October 21, 2015 Posted October 21, 2015 Also I have to say that mine is a totally different engine. I'm not sure that my advice even applies to yours. Quote
BaitMonkey1984 Posted October 21, 2015 Posted October 21, 2015 I had a 7.5hp game fisher on my aluminum some years ago. The engine did the same thing, and it was a carb problem. I would re-check the carbs and the jets. Also, as to the spark plugs I would make sure you get the right brand for the engine. For example, they say for Hondas use NGKs, for Johnson it may be Champion. I had an issue once before due to not properly gapping the plug, so make sure that is done correctly as well. Quote
Super User Way2slow Posted October 21, 2015 Super User Posted October 21, 2015 First, check the compression with engine warmed up. If I remember right, those carbs are fixed orifice. To adjust them requires changing jets. Proper cleaning is critical so I would question the rebuild on the carbs because that would be my next action. The power packs on those motors are not that reliable when they get some age on them so that would be my next point of attention, but I think it'[s most likely the carbs. Quote
Fisher-O-men Posted October 21, 2015 Posted October 21, 2015 You have already rebuilt the carbs. Power pack problem. Will it fall off of plane after about 1 miniute of WOT? Quote
Super User Way2slow Posted October 21, 2015 Super User Posted October 21, 2015 Not trying to question his abilities, but just because he put a kit in the carbs does not mean they were properly cleaned. I've been doing them many years and very experienced with carbs and there has been more than once when I've had to go back into one a second time. Some of the orifices in those are fairly small and it only takes one two thousandths of obstruction to cause all kinds of head aches. Just taking one apart and cleaning it up a little don't always get it. All the jets have to be taken out and cleaned with a tooth pick (you should never use a metal item to clean a jet because it damage the orifice or open it up more) If they have those disk covers over port access points, most people tend to leave them alone, me included because they can be a royal pain, but sometimes they have to come off the get them clean. A long welding tip cleaner and compressed air are your best friends for cleaning one. If it's a metal carb, it needs to be soaked in some hydro seal carb cleaner. The bog he is getting is crabs about 95% of the time. The low speed or mid speed orifices have some obstruction them. I have also worked on carbs that someone else did and put jets back in the wrong spot. Quote
gbryant04 Posted October 21, 2015 Author Posted October 21, 2015 Once on plane it continues to run like a champ and won't stop until you let off the throttle. Only at low rpm range trying to start taking off. Yes it does have the fixed orifices. Looks like I may need to take the carbs back off and check them all one more time. Also had a local mechanic mention using non ethanol 93 . I have been using ethanol 93 with seafoam. Think this would have any positive effects? Quote
Super User Way2slow Posted October 21, 2015 Super User Posted October 21, 2015 Not really. When you go back into them, make sure those little micro size holes in the venture on each side of the throttle plate are clean. Take the low speed jet out verify the size number on it and clean it good with a tooth pick, Use brake cleaner or carb cleaner with the plastic stem and blow through the passage in the carb and blow it out with compressed air several times. Make sure you get a good spray out of each of those holes with crab/brake cleaner. With the jets out, a welding tip cleaner can be use to clean the passages. Do the same thing with the mid range and high speed jet. Here's a link that might help you some. http://epc.brp.com/Index.aspx?lang=E&s1=679b8d09-6aef-4815-9690-08ac441c8d5e click the arrow in the pull down, select Johnson then your year, then model and then carbs It changed, you have to click on view parts catalog first. You don't want to put your email, or you will get piles of junk email Quote
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