Motor gets stuck at 2000 rpm

[BigWake]

hello I am new here so sorry if this has been a topic befor my time.BUT i have a Mercury 1400 140hp that has started to get stuck at 2000 rpm and does not want to plane out. if you leave it there for a while it will start to gain RPM very slowly and then plain out...but when you slow back down its the same ole BS over again.Could this be a timming problem and if so how does the timming just get all messed up on its own?

 

[BigWake]

Re: Motor gets stuck at 2000 rpm

Anyone?Really could use some help here

 

[Plainsman]

Re: Motor gets stuck at 2000 rpm

Since no else chimed in, does priming the bulb make a difference? Or if you choke it does anything change?

 

[kingsnakejr]

Re: Motor gets stuck at 2000 rpm

Sounds like a fuel obstruction to me. Make sure fuel filter and lines are clear. As fuel pump builds pressure the obstruction moves enough to allow enough fuel to flow for engine to plane out. If no obstruction is found, rebuild fuel pump. If this doesn't help be patient and someone with more knowledge than me will help you. Hope this helps.
ks

 

[Chris1956]

Re: Motor gets stuck at 2000 rpm

Likely it is a set of dirty carbs or misadjusted idle mixture. Did you post the year of the motor?

 

[BigWake]

Re: Motor gets stuck at 2000 rpm

The year of the motor is 1978 1400 140 hp.....I have looked for a fuel filter and can not find one is this in the fuel pump?


If i choke the motor it dies.


OK the 1st time this yr that we took it out it ran great i noticed by the end of the weekend it was having a harder time taking off...seem to be getting a very small studer in the motor when under a load.

2nd time out when i went for the 1st ride seem ok but the longer it runs the worse it would get untill the boat would just not plain out for very long periods of time and even at a full plain just did not seem to have the power it should.

now it just runs like crap...lol SO i am going to check the timming out clean carbs as one said and put in new plugs and see what this gives me...


thank you!!!!

 

[Chris1956]

Re: Motor gets stuck at 2000 rpm

Wake, On the starboard side of the motor, mounted on the lower cowling is the fuel pump. The front of the fuel pump has a black plastic cup held on by a single stainless phillips head screw. Remove the screw and the cup and you will find the fuel strainer. Clean and reinstall it. Also under the brass fittings that screw into the carb covers is a fuel screen. These almost never get dirty.

 

[BigWake]

Re: Motor gets stuck at 2000 rpm

Well checked the compression today and was as follows

#1=124 psi
#2=124 psi
#3=124 psi
#4=124 psi
#5=125 psi
#6=124 psi

I think that is good right?

Also when pumping the primer bulb i noticed fuel dumping out of the middle carb i am guessing that it should not do that right? lol

 

[BigWake]

Re: Motor gets stuck at 2000 rpm

Wake, On the starboard side of the motor, mounted on the lower cowling is the fuel pump. The front of the fuel pump has a black plastic cup held on by a single stainless phillips head screw. Remove the screw and the cup and you will find the fuel strainer. Clean and reinstall it. Also under the brass fittings that screw into the carb covers is a fuel screen. These almost never get dirty.

hey i checked that and it was clean....I think i have some sticky floats in the carbs.after i get the carbs clean and the timing set im going to try and take it out to see how we do.

 

[Plainsman]

Re: Motor gets stuck at 2000 rpm

Wake,

The compression is good. Anything over 100 and with 10% of each other is good.

If you have fuel leaking out of the carb throats, then you need to get carb rebuild kits. Take the carbs off and soak them in carb cleaner. Use the rebuild kit to reassemble.

The fuel leaks out because the needle is sticking open.

 

[BigWake]

Re: Motor gets stuck at 2000 rpm

ok.....what would make it pop at 2000-3000 rpm?didn't do that untill new plugs and cleaning the carbs.... seems to run alot better now but has a pop at 2000-3000 rpm now...is that a lean pop?

 

[BigWake]

Re: Motor gets stuck at 2000 rpm

we are going to dive into this thing again today...its seems to pop threw all the RPM range over 2000 upto 4500.This is a new trick by the way.lol silly motor also once i get this running right should i off it and get a newer motor or just keep to this one? seems for how much the newer motors are i would be better off going all the way threw this one

 

[tredragon]

Re: Motor gets stuck at 2000 rpm

I feel your pain. Debating on whether to keep trying on this boat or not. Wife is getting tired of family outings that involve me cursing at the boat and wrenching on the water the entire time... not to mention 10mph "cruises" back to the launch at the end of the day.

 

[BigWake]

Re: Motor gets stuck at 2000 rpm

OK crazy thought here...lol could my charging system be failing in turn my battery dieing causing my motor to not produce the correct amount of spark there for making my motor BOG at WOT?would explain why the boat would run worse and worse the longer i used it....AND also cause the back firing when trying to reach RPM's over 2000 because the lack of spark???

 

[Chris1956]

Re: Motor gets stuck at 2000 rpm

If that motor has a distributor, low battery voltage couls cause ignition problems. Check the charging system with a voltmeter. The motor should have slightly greater battery voltage when running on fast idle than ideling or off. If not, the rectifier is likely blown.

If the motor has six coils and no dissy, the spark is unaffected by battery voltage.

 

[BigWake]

Re: Motor gets stuck at 2000 rpm

It does have a distributor i have the battery charging right now and will test this out in a few hrs..would explain why it ran great the 2 times out and got worse the more that it ran....i hope this is it

 

[BigWake]

Re: Motor gets stuck at 2000 rpm

well seems like i might have found the little demon that was cause me all the head ackes.If i pull the battery cable off while its running the motor dies right now so i am guessing that is my problem i hope....lol

 

[hkeiner]

Re: Motor gets stuck at 2000 rpm

It has been my understanding that pulling the battery cable off the battery while the motor is running is not a good idea because it can cause components of the charging or ignition system to fail. It is better to use a voltmeter to test whether the system is charging OK or not.

Also, a DVA meter and a spark tester would be useful for determining if the spark is failing during engine bog.

 

[BigWake]

Re: Motor gets stuck at 2000 rpm

just to let you all know where i am at...the battery was all but dead gave it a full charge and the motor sounds brand new again...i have not had a chance to put the boat in the water yet but i think my stator is bad and when the battery was dieing the motor would run worse and worse.Think i need a stator.


also it still has that little pop while running over 2000 rpm and i noticed fuel dripping put of the carbs even after being cleaned up...

 

[Chris1956]

Re: Motor gets stuck at 2000 rpm

Wake, Check the voltage at the battery when the motor is running. The voltage should increase when you run the motor up to fast idle 1500RPM or so. If not you likely fried your rectifier when you disconnected the battery cable. DO not do that in the future, if you want the igniton system to survive.