7.5 Gamefisher only runs with 1/2 choke

[RandyJ]

Seems to be a good running little motor. Hard to start. Only runs with 1/2 choke. Idles slow enough to troll... shakes and is too noisy to catch fish. Not looking for help with the fish but sure wish someone had an instant answer to why it only runs with 1/2 choke... with choke off it slows down or dies. I've already cleaned carb and put in a complete new carb kit, float appears to work fine with new needle and seat. Float sits level with carb when turned upside down...so, I guess it's right. I'm guessing that since it has plenty of air already it runs better by limiting the air by using the choke which suggests to me that it is getting air elsewhere... maybe carb gasket. Any suggestions would greatly be appreciated.

 

[lowkee]

Re: 7.5 Gamefisher only runs with 1/2 choke

I think you are on the right track, you may be sucking air where the carb meets the engine. You may also have a clogged jet, something a carb kit won't help you with, you will need to wire brush all of the tiny passages and make sure they are squeaky clean.

I used to have that same motor and boy do I recall the rattle and noise it made! It sure kicked the butt of my old Mercury 6HP for speed, though. I just used the 6HP for trolling, as the noise was just unbearable for me (forget the fish!) when trolling.

That old beauty (read: ugly, noisy, shakey hunk) will run forever!

 

[RandyJ]

Re: 7.5 Gamefisher only runs with 1/2 choke

I'll vote for the carb base gasket leaking. It takes a 3/8" wrench on those nuts and can hardly get them to break loose or tighten them. Maybe I should try a 9mm to see if I can get a better grip on the buggers. I do have another base gasket I could try but I'm just about tired of working on these motors and ready to do some riding...

 

[mcgyver6857]

Re: 7.5 Gamefisher only runs with 1/2 choke

I'm having a similar problem with the same motor. It's only at higher rpms though and I recently rebuilt the carb as well. Came out with the same results as I had before. The motor runs great at quarter choke but doesn't seem right eh. Hopefully can get some good ideas with this thread, please post your results.

 

[RandyJ]

Re: 7.5 Gamefisher only runs with 1/2 choke

If it's at higher rpm I would suspect not enough fuel getting to it or an electical problem. Pump the fuel line bulb really hard and see if there's any leaks. I've seen backfiring cause gaskets to blow out on other engines so you might also want to look at the carb base gasket. Assuming that the carb is cleaned out pretty good you can tinker with the fuel mixture screw. Depress the funky star thingy then count the number of turns you have to screw it in with a screwdriver till it bottoms out. It should be about 1 1/2 turns... then readjust while running at high speed. If nothing else then check the spark plug. If you've had the fly wheel off then look under it again to see if there's any wire that may be too close or cracked and causing it to jump. Mine runs smooth but just looses power if I don't choke it. If it's a firing problem it will usually run with a miss. A carb problem usually just makes it idle rough or run sluggishly. Bad, out of ajustment or dirty points, from my experience, makes it difficult to run at low speeds.