brianontheroad
Cadet
- Joined
- May 20, 2008
- Messages
- 6
I have a 2001 Mercury 8 Horsepower 2 stroke. We're down in the bahamas on our sailboat so parts are fairly hard to come by (like a gasket kit for carb....) but I've been doing my best to figure out why we're suffering from a loss of about 1/3 horse power (just an estimate) The 8 is on my little RIB and used to plane the two of us out just fine (but I've always had to run it with the primer bulb out to get full power) but lately it will only plane out with just me and even then it's obviously slower and running somewhat rough
I cleaned out the fuel filter, all the fuel lines and gave my fuel tank a good cleaning as well. Still not getting full power, I pulled the plugs and they were all black, so I thought the issue was it was running too rich (since the primer bulb was out definitely a richer mixture right?), I cleaned the plugs and took apart the float bowl -- the needle valve looks like a nice fit but I don't think the float is working properly, I measured the clearance on the float and it was 1/8 of an inch off (1 and 1/8" clearance from bottom of float to top of carb with carb inverted instead of factory 1")
I adjusted the fork that the float sits on on to get the proper clearance but the engine still runs rough, it idles, starts on the first pull and is totally reliable -- I do have to pump the bulb every day or so I am thinking there is still too much fuel going into the carb (or not enough air....) or could it be a timing issue? Could my high speed jet be clogged and that's why it get's more power with the primer bulb out and the enrichner circuit open? Is there a way to adjust the mixture for any circuits other than the low speed/idle? It seems to run better with the cover off and it gets lots of air forced through the carb but it could just be louder and I think it's running better
The #1 reason I think it's getting too much fuel is because it seems to run GREAT right before I run out of gas -- it'll just take off
Any advice on things I can do short of rebuilding the carb? Any advice on tuning this particular mercury? What else should I be checking? This is my first outboard so I'm still learning.....but it seems to be burning a lot of gas, (not too smoky but I tearing through gas which in the bahamas is pricey)
Any more advice on getting the float just right?
Thanks!
Brian
I cleaned out the fuel filter, all the fuel lines and gave my fuel tank a good cleaning as well. Still not getting full power, I pulled the plugs and they were all black, so I thought the issue was it was running too rich (since the primer bulb was out definitely a richer mixture right?), I cleaned the plugs and took apart the float bowl -- the needle valve looks like a nice fit but I don't think the float is working properly, I measured the clearance on the float and it was 1/8 of an inch off (1 and 1/8" clearance from bottom of float to top of carb with carb inverted instead of factory 1")
I adjusted the fork that the float sits on on to get the proper clearance but the engine still runs rough, it idles, starts on the first pull and is totally reliable -- I do have to pump the bulb every day or so I am thinking there is still too much fuel going into the carb (or not enough air....) or could it be a timing issue? Could my high speed jet be clogged and that's why it get's more power with the primer bulb out and the enrichner circuit open? Is there a way to adjust the mixture for any circuits other than the low speed/idle? It seems to run better with the cover off and it gets lots of air forced through the carb but it could just be louder and I think it's running better
The #1 reason I think it's getting too much fuel is because it seems to run GREAT right before I run out of gas -- it'll just take off
Any advice on things I can do short of rebuilding the carb? Any advice on tuning this particular mercury? What else should I be checking? This is my first outboard so I'm still learning.....but it seems to be burning a lot of gas, (not too smoky but I tearing through gas which in the bahamas is pricey)
Any more advice on getting the float just right?
Thanks!
Brian