Tweet
Guys,
Help me understand the best way to track down a fuel flow issue (I believe).
While getting this older engine working we had a lot of troubleshooting but it's been running fine after several carb cleanings (rebuilt) and replacing may items including fuel pumps.
While troubleshooting and test (which was solved by recleaning the carbs) we did our testing on a portable tank with no filter other then the small screen unit on the engine. Then we reintroducted the internal tank (removed, cleaned during our restoration) and it still runs great...
We then put the fuel filter housing and filter (10 micron) on the system and it runs like crap. Over 3K rpm it doesn't do so well. Squeeze ball is not firm nor round (kind of sucked in). Tried a 2nd filter assembly as we suspected a leak and same issue. Take filter off...runs great.
One buddy thought our newer bulb felt funny too...so...
Should we put a vac gauge on it? We are pretty sure introducing the filter assembly increases the vac pressure enough to cause the issue.
Should we try another primer bulb?
Consider one of the new pumps to be weak?
Something else?
What steps should we do to troubleshoot this?
Lastly...why does the engine need the screen filter in it if Yamaha expects you to have a spin on filter in the system? Why a filter with bigger holes downstream?
Help me understand the best way to track down a fuel flow issue (I believe).
While getting this older engine working we had a lot of troubleshooting but it's been running fine after several carb cleanings (rebuilt) and replacing may items including fuel pumps.
While troubleshooting and test (which was solved by recleaning the carbs) we did our testing on a portable tank with no filter other then the small screen unit on the engine. Then we reintroducted the internal tank (removed, cleaned during our restoration) and it still runs great...
We then put the fuel filter housing and filter (10 micron) on the system and it runs like crap. Over 3K rpm it doesn't do so well. Squeeze ball is not firm nor round (kind of sucked in). Tried a 2nd filter assembly as we suspected a leak and same issue. Take filter off...runs great.
One buddy thought our newer bulb felt funny too...so...
Should we put a vac gauge on it? We are pretty sure introducing the filter assembly increases the vac pressure enough to cause the issue.
Should we try another primer bulb?
Consider one of the new pumps to be weak?
Something else?
What steps should we do to troubleshoot this?
Lastly...why does the engine need the screen filter in it if Yamaha expects you to have a spin on filter in the system? Why a filter with bigger holes downstream?