Stalling above 10 mph...

[surfer00]

I took the boat (89 Sea Ray, 115 4 banger merc) out this weekend. A couple of things occurred.

First my throttle control wasnt working properly and when i checked under the cover I found that the little plastic bracket that holds the throttle cables in place had broken, leaving the 2 cables swinging freely. I was able to wire it together so I could take some visiting relatives on the lake.

When I was out on the lake and gave it gas, it ran fine and right after planing it would completely stall out. It would start up again just fine and I could drive it at about 10 mph ok, but anything higher it would get to speed and then die.

Background - I have to keep this boat away from home at a storage lot and bring it home every month or so for a bath. Last weekend I had brought it home and took off the engine cover to replace the plugs. When I was replacing the engine cover I really struggled to get it back on properly. I was having trouble lining up the pins that the cover rests on.

The reason I mention this is because that is when I apparantely broke the clip the holds the cable and maybe I did something else that is related to the stalling.

My question is - the stalling out seems to me to be fuel related, but I know little about boats. Any place where I should start the process of elimination?

Thank you for any help!

 

[rodbolt]

Re: Stalling above 10 mph...

check for any fuel restrictions,if it hasnt been done recently a fuel pump rebuild may help.
then its most likly on to the carbs.
have you tried pumping the fuel primer bulb when it starts losing power? does hitting the "choke" button have any affect when it starts losing power ?

 

[surfer00]

Re: Stalling above 10 mph...

Hi Rodbolt,

Thanks for the reply. I didnt try punping it when was dying because it just DIED. No loss of power or sputtering.

I did however squeeze the bulb after the first time it died and it seemed empty. I have only squeezed it before starting for the first time, so I dont know what it would normally feel like. I always assumed it stayed hard.

I didnt check the choke button either. I was surprised that it would start right up again after it died. I didn't need to give it throttle or anything, just started it in the idle position.

 

[mykrilee]

Re: Stalling above 10 mph...

you might see if your fuel filter needs changing.

 

[surfer00]

Re: Stalling above 10 mph...

Thanks mykrilee,

I'll check the filter out. I've been searching online to see if I can find a series of checks to track down fuel problems. I guess the filter is a good place to start!

 

[hkeiner]

Re: Stalling above 10 mph...

Any place where I should start the process of elimination?

​

Mercury issued a Service Advisory on fuel starvation, describing how to check the vacuum level required to draw fuel from the fuel tank to the pulse driven fuel pump, how to check for air leaks in the fuel supply system, and how to check the condition of the pulse driven pump. All you need is a vacuum gauge, T-fitting, and clear hose.​

If you are unable to readily resolve your problem following the very good advice you already received in this thread, you might consider trying the troubleshooting steps described in the Service Advisory. They may help you to either definitively confirm or eliminate a group of fuel starvation type causes of engine stalling. For example, if fuel starvation is eliminated as a condition, you can avoid needlessly inspecting/replacing the many components upstream of the fuel pump and instead focus on things downstream of the fuel pump, such as dirty carbs, incorrect link and sync settings, ignition failure, etc. On the other hand, if the tests determine that you do have a fuel starvation condition, the test results will greatly narrow down the possible culprits, depending on which fuel starvation test shows a problem.​

http://www.marinepartsman.com/Mercury-Marine-service-bulletins/Mercury-Mariner/2001/EN_17.PDF