50 hp 2004 mercury rpm's drop

[mtrproblems]

Motor starts up fine, runs a little roughly at low rpms, but at wot the engine runs perfectly for 5-10 seconds at 4900 rpms and then drops to 3000-3200 rpms and wont run any faster. If you drive in low rpms (800-1000) for 5 min, you can get up to 4900 rpms before it drops back down again. Any idea what's up? Everything is close to brand new and even have a water/fuel seperator installed.

 

[JB]

Re: 50 hp 2004 mercury rpm's drop

Howdy, problems.<br /><br />Welcome to iboats. <br /><br />I will move this to Merc troubles.

 

[bassman283m]

Re: 50 hp 2004 mercury rpm's drop

Is it a 4 stroke? How long have you had it? Has it always done this?

 

[Laotzu]

Re: 50 hp 2004 mercury rpm's drop

I have a 1991 50hp that does the same thing. Runs smooth after it drops down to about 3k rpm's...no missing, smoke, purr's like it should, but just won't accelerate. I have been trying to troubleshoot for a while now. <br /><br />Anyone who helps mtrproblems will also help me. Two birds with one stone.

 

[mtrproblems]

Re: 50 hp 2004 mercury rpm's drop

Its a two-stroke, had it 3 months. It hasnt always done this. Mechanic has looked at it done a lot of tests, suggested the fuel-filter, it hasnt helped.

 

[mtrproblems]

Re: 50 hp 2004 mercury rpm's drop

I think it may be the fuel connector (my terminology may be wrong) where the fuel hose enters the motor that is sucking air resulting in rpms dropping. I'm gonna purchase a new connector and see if that fixes the problem. Hope I may have found a solution to our problem Laotzu.

 

[Silvertip]

Re: 50 hp 2004 mercury rpm's drop

When it tends to die off, activate the choke (push in on the key) momentarily. If that doesn't do anything, try squeezing the primer bulb a time or two. If the engine picks up you indeed have a fuel delivery problem. Pickup in the tank, bad primer bulb, fuel connector, fuel pump, to name a few.

 

[Laotzu]

Re: 50 hp 2004 mercury rpm's drop

mtrproblems..how do you know the connector is sucking air?

 

[mtrproblems]

Re: 50 hp 2004 mercury rpm's drop

didnt, the connector just felt really loose.<br />Had another mechanic check it, turns out some foreign object was restricting gas flow in the carb.(no idea how anythihng would get in there) Engine runs great now. One of your carbs probably isnt working for some reason.

 

[Laotzu]

Re: 50 hp 2004 mercury rpm's drop

Not it. I had it in the shop and they checked out all the fuel systems and all were ok. Flushed the carbs, etc. I tried a remote fuel source, but still does it. Guess I'll have to take it in again unless someone here can help me.