1990Onan520-H 15 #1 Posted August 10, 2020 Hey all. I've got a 96 416 hydro that started surging on me. So I pulled the carb and am cleaning it out since the machine sat outside for probably 20 years not being used. But during cleaning I saw this piece on the side of the carb with 3 screws on it. I want to pull it to clean it out, but I am having trouble finding a gasket or even figuring out what it is. Does anyone know what this is or where I can get a new gasket for it? 1 Share this post Link to post Share on other sites
lynnmor 6,775 #2 Posted August 10, 2020 Onanparts.com has the accelerator pump parts. I don’t like those carbs and replace them with older models that have no pump. 2 Share this post Link to post Share on other sites
1990Onan520-H 15 #3 Posted August 10, 2020 3 minutes ago, lynnmor said: Onanparts.com has the accelerator pump parts. I don’t like those carbs and replace them with older models that have no pump. I have a 1991 520-H carb. Can I use that? I'm assuming it would inject too much fuel, but is there a way for me to take the jets out of the 416 carb and throw them in the 520 carb to make it run right? Also just curious why you don't like the 416 carb I currently have? Share this post Link to post Share on other sites
peter lena 8,064 #4 Posted August 10, 2020 agree with lynnmor on that carb issue , why not just swap it out with a carb that has no issues, make the problem go away , pete Share this post Link to post Share on other sites
1990Onan520-H 15 #5 Posted August 10, 2020 Just now, peter lena said: agree with lynnmor on that carb issue , why not just swap it out with a carb that has no issues, make the problem go away , pete I don't have a carb that has no issues. I'm sure any old carb I get will need a refresher anyway. While it's off I may as well clean it out. Why don't you like this carb either? Share this post Link to post Share on other sites
peter lena 8,064 #6 Posted August 10, 2020 1990onan520-H , while i do not have a 416 hydro, i can say if there is a known problem area that has been exposed on the site , i will look into it if it applies , to me. having been improving on a number of areas , if are having a chronic problem and a quick fix exists , why not look into it? or tell us what you have solved the issue with , pete Share this post Link to post Share on other sites
1990Onan520-H 15 #7 Posted August 10, 2020 1 hour ago, lynnmor said: Onanparts.com has the accelerator pump parts. I don’t like those carbs and replace them with older models that have no pump. Guessing this would be the kit? https://onanparts.com/index.php?main_page=product_info&products_id=263&zenid=f06f2863a312922dbac8d042d2a8c48d I'm leaning toward just fixing what I have, but am curious as to why this design carb is maybe not as good before I spend the money on this kit and new gaskets for it etc. Share this post Link to post Share on other sites
tom2p 2,393 #8 Posted August 10, 2020 (edited) I'll jump in - until lynmor can weigh in the accelerator pump adds complexity ; another area that can require maintenance and/or cause an issue accelerator pump can also adversely impact the engine - more specifically the oil and then the engine if it is supplying the engine with too much fuel (which then can be 'unburnt' and dilute the oil) ... this can especially be a problem if/when the engine continually surges and accelerator pump provides excess fuel Edited August 10, 2020 by tom2p 1 Share this post Link to post Share on other sites
