Mercury 7.5 issues/questions

Jis4Jeep

Seaman Apprentice
Joined
Jul 20, 2010
Messages
45
So I am the new guy that just bought his first jon boat 24 hours ago. I tool it out on the lake and I am certain there where some folks who live on the water just getting a kick out of my wife and I along with kids completely having no clue what we are doing. Motor started first pull I turn the throttle knob ( I dont know what its called) to shift and then put the motor in Forward. we drove out for about 2 minutes to the middle of the lake and the motor sounded like it was chocking and shut off. I tried to start it back up but not knowing anything it was still in forward and the the start rope wouldn't pull (at the time I did not know that theres a safety on the motor must be in Neutral Im learning) At the time I feared the worse the motor seized so I grabbed the oars and paddled us back to the dock.

At the dock I waited a few minutes and tinkled with the motor making sure the knob was on start and the switch was on neutral ( I read the notice on the motor) and i pumped some gas and it started. I ran it for a little bit but it shut off again. I pulled it started so I told the family get back in we are going to try this again. a few minutes go by and we are stuck really far now from the dock. No biggie my 12 year decided he would be the big boy and stepped up and started to paddle while I worked on the motor.

This happened several times but we made it back.
The problems I have cause I dont know:

The fuel line goes on two ways one way it just pushes on the other way it pushes on and twist so that it locks, so I gather thats the way it goes.

On the throttle theres a knob that looses and tightens at the very end/tip I have no idea what it is but when i messed with it the motor started right up. but then again would die almost like on a car motor would do if the idle was too low or not getting enough fuel. The fuel hose seems kind of long but what do I know. Can anyone tell me what the knob on the twist handle is for? I plan on messing with it in the morning but if I have no luck Im going to take it to a marine shop. I really dont want to spend a bunch of money but it looks like I may have to to get it running right. The last owner said he had the motor serviced 2 months ago but you know how that goes people will say anything to sell a boat.

Last thing it seems like the twist handle rotates freely to the shift side but when I twist towards the fast side it does not turn very far. Maybe I am thinking like a motorcycle throttle that has a 3/4 rotation on the handle. Thanks for any help I can get in advance.
 

bob1340

Petty Officer 1st Class
Joined
Jun 12, 2010
Messages
287
Re: Mercury 7.5 issues/questions

No idea what the knob on the end of the tiller is. I have a '70 7.5 and it has no knob on the end. The throttle can only go so far while in neutral. Once you put it in gear the throttle can roll on more.

Get an owners manual for you motor and figure it out before you head out to the middle of the lake.
 

Jis4Jeep

Seaman Apprentice
Joined
Jul 20, 2010
Messages
45
Re: Mercury 7.5 issues/questions

No idea what the knob on the end of the tiller is. I have a '70 7.5 and it has no knob on the end. The throttle can only go so far while in neutral. Once you put it in gear the throttle can roll on more.

Get an owners manual for you motor and figure it out before you head out to the middle of the lake.

Yeah I found a web site for mercury motors and tride to look up but my numbers didn't match what they where showing online. I'll be doing some more research at least the trolling motor works.
 

the beave

Seaman Apprentice
Joined
Sep 11, 2007
Messages
44
Re: Mercury 7.5 issues/questions

what kind of gas tank do you have? sounds like its not getting vented causing a lack of fuel.
 

Jis4Jeep

Seaman Apprentice
Joined
Jul 20, 2010
Messages
45
Re: Mercury 7.5 issues/questions

what kind of gas tank do you have? sounds like its not getting vented causing a lack of fuel.

Here is a picture of the gas can and gas line:

gastank.jpg


gasline.jpg
 

Jis4Jeep

Seaman Apprentice
Joined
Jul 20, 2010
Messages
45
Re: Mercury 7.5 issues/questions

Well you where right Beave I feel like a dud! The vent on the gas cap was closed so there wasn't free flowing gas. I went outside opened the vent she started up and ran like a champ. I shut it off and started it again no problem. Thanks for you help I feel allot better now. Back to the lake and hopefully we will have no more issues before our weekend trip up north!
 

bob1340

Petty Officer 1st Class
Joined
Jun 12, 2010
Messages
287
Re: Mercury 7.5 issues/questions

Well you where right Beave I feel like a dud! The vent on the gas cap was closed so there wasn't free flowing gas. I went outside opened the vent she started up and ran like a champ. I shut it off and started it again no problem. Thanks for you help I feel allot better now. Back to the lake and hopefully we will have no more issues before our weekend trip up north!

LOL. I think we are allowed to make 7 mistakes a day. I average 12. I have that same type of gas cap and have done the same thing many times. I usually forget to tighten it and gas squirts in my Jeep or truck.
 

Jis4Jeep

Seaman Apprentice
Joined
Jul 20, 2010
Messages
45
Re: Mercury 7.5 issues/questions

LOL. I think we are allowed to make 7 mistakes a day. I average 12. I have that same type of gas cap and have done the same thing many times. I usually forget to tighten it and gas squirts in my Jeep or truck.

Yeah I told the guy at Bass Pro what I did and the look on his face was like I had no business having a boat. Hopefully all is good and I dont have anymore silly incidents.
 

Downwindtracker2

Petty Officer 2nd Class
Joined
Jun 25, 2008
Messages
110
Re: Mercury 7.5 issues/questions

That twist knob is for locking the throttle at a speed. The factory owners manuals are still available,though I'm not sure they are worth the price. The Factory service manuals are though.
 

Jis4Jeep

Seaman Apprentice
Joined
Jul 20, 2010
Messages
45
Re: Mercury 7.5 issues/questions

That twist knob is for locking the throttle at a speed. The factory owners manuals are still available,though I'm not sure they are worth the price. The Factory service manuals are though.

Thanks I explained to someone today about it and I actually referred to it as a motorcycle throttle lock but would of never imagined that is what it was for. Cruise control for a boat sweet!
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: Mercury 7.5 issues/questions

I do hope when you went outside and started it up that it was running in a barrel with water up over the waterpump...

That said, motor is new to you, you're new to the motor. Might be a good idea to at the very least find an owner's manual, and beyond that maybe get a service manual. A new waterpump impeller is a good idea, particularly if the previous owner doesn't know when it was last changed out.
 

Jis4Jeep

Seaman Apprentice
Joined
Jul 20, 2010
Messages
45
Re: Mercury 7.5 issues/questions

I do hope when you went outside and started it up that it was running in a barrel with water up over the waterpump...

That said, motor is new to you, you're new to the motor. Might be a good idea to at the very least find an owner's manual, and beyond that maybe get a service manual. A new waterpump impeller is a good idea, particularly if the previous owner doesn't know when it was last changed out.

Yes sir! I put a big cooler under full of water. Today I actually took apart the water pump to inspect impeller and sure toasted so it's a great thing that I had the fuel problems so I didny damage the motor. Order a whole kit it will be at the shop for pick up Monday. Also order the cd manual on eBay. Thanks everyone for help ive learned allot the last few days.
 

the beave

Seaman Apprentice
Joined
Sep 11, 2007
Messages
44
Re: Mercury 7.5 issues/questions

Glad I could help, been there done that...lol!
 
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