1994 evinrude 120 engine bogs out

[steve in va]

my 94 evinrude 120hp motor is bogging out and nobody can figure out why. i have had the boat for 5 yrs and no problems at all untill now. i was running wide open when the motor just shut down. put it in nuetral started fine, goes into gear and runs fine untill you put a load on it(about 1500rpm or higher) then it runs rough like it's choking out, but if you pull it back in nuetral it clears up. i drained all fuel and changed all filters , added 2 cans of sea foam and 2 bottles of heet to 45 gals of fresh gas took it out and it ran great for 1 hour then shut down again. boat is in shop now they ran it wide open on dyno and it didn't act up so now they are sending all electronics(stator, power pack etc...) to be tested, it will be a week or so before i get results does anyone have any idea at all? the shop is raping me at 95 per hour and the say they can't fix it unless it is acting up please help steve

 

[HighTrim]

Re: 1994 evinrude 120 engine bogs out

Sending them out to be tested? Why in the world would they have to do that??

Have you checked the anti syphon valve and the tank vent?

 

[steve in va]

Re: 1994 evinrude 120 engine bogs out

chris thanks for the reply... as for sending them out thats what i said, they said they had to remove all components of electrical system and send them to some marine electronics specialist in alabama or somewhere... they said all pieces will be tested together on a machine that simulates the load of actually being on the water, i guess they don't have that capability at that shop... does sound "fishy" anyway as for tank vent i think it is ok because when i overfilled the tank at the gas station fuel came gushing out on to the ground, and as for the "anti syphon valve" not even sure what that is (i am new to the boating mechanics world) i did use a long piece of garden hose to "syphon" the old gas out so it either has no valve or the "anti" in the word antisyphon is not working i am racking up a huge bill so far and they don't even know whats wrong with it because it is not acting up in their shop

 

[kenmyfam]

Re: 1994 evinrude 120 engine bogs out

Just a stupid thought.....but how is the hub on the prop ?????? may just be spun ???? enough to hold up till 1,500 rpm.

 

[steve in va]

Re: 1994 evinrude 120 engine bogs out

no its not the hub, i would think the shop would have seen that when they hooked it up to the dyno, they ran it wide open for awhile on dyno with no problems as far as they are concerned the boat runs great ha ha it is problem that happens after awhile of running it seems

 

[HighTrim]

Re: 1994 evinrude 120 engine bogs out

An anti syphon valve is a device that prevents fuel from returning back down the line in which it came if a syphon action were to occur. Locate your fuel tank. The valve will be where the rubber fuel line attaches to the tanks fitting. They are made out of aluminum and are a couple inches long. These buggers are known for sticking in a semi closed position, creating a vaccuum which can create a problem. Remove the fitting, and take out the spring, ball and ball seat. It will now be a straight through fitting. Hopefully this cures your problem. You could also simply get a new valve if you wish, because now the fuel is able to flow backwards into your tank when your motor is not running. I find the fuel primer bulb stops this flow though. Your fuel bulb is not sucking flat at all is it? That would indicate further that this is your problem.

Also have a look at your vent none the less, ensuring that there is no debris present. It will be located beneath your fuel fill likely, on the starboard side of the vessel.

 

[HighTrim]

Re: 1994 evinrude 120 engine bogs out

Also, when were the carbs last rebuilt? May be time for a bath and rebuild. Check to see if the timer base (starboard side, under the edge of the flywheel, linked to the throttle lever) moves smoothly without sticking when you advance the throttle.

Take the airbox cover off & observe whether the throttle plates are parallel.

Also, the timer base should start it's travel before the throttle plates start to open, or else your girl will die when you give her the throttle.

 

[steve in va]

Re: 1994 evinrude 120 engine bogs out

the carbs have not been rebuilt since i have owned the boat (at least 5 yrs) but here is where i am confused... if the carbs were gummed up wouldn't it run bad from start up to stopping? the mechanic said if the carbs were the problem then that would show up when they ran it on the dyno i guess because there might be some sort of shaking to loosen up any trash or debris that might be floating around in there while running at high rpm also the anti syphon valve sounds like a good place for me to try but the gas tank is located under the floor and there is no way to get to it to see(1986 hydra sport ceter console/1994 evinrude 120 outboard) what about a test from the fuel line to see if valve is there by blowing air into line, if air goes into tank the valve is either bad or not present right? also that should blow any excess air out of the tank vent on side of boat and should eliminate that question as well ? i do appreciate all of the help

 

[wilde1j]

Re: 1994 evinrude 120 engine bogs out

no its not the hub, i would think the shop would have seen that when they hooked it up to the dyno, they ran it wide open for awhile on dyno with no problems as far as they are concerned the boat runs great ha ha it is problem that happens after awhile of running it seems

The marine dyno I used to use required removal of the customer's prop and installing a splined adapter to the dyno hydraulic load device. You would never know if the prop was OK or not. Very simple to check for slipping hub by marking the inner hub and the outer prop, running at high load, the see if the marks moved relative to each other.

 

[steve in va]

Re: 1994 evinrude 120 engine bogs out

i am no mechanic by any stretch of the imagination... but wouldn't the engine rev really high if there was slipping of the prop? and yes that is exactly the way they described how their dyno test was performed...my problem is that the boat runs fine and then just starts to fall on its face for no reason whenever it feels like doing so... it seems like a fuel issue or a vacuum issue or like another gentleman said possibly the engine control module may be overheating...the problem is random and i am going nuts here steve

 

[wilde1j]

Re: 1994 evinrude 120 engine bogs out

Yes Steve, it would rev high. Have you tried an alternate fuel tank to eliminate something in the fuel supply as an issue?

Have you tried activating the choke/primer (or squeezing the primer ball) whenever the motor slows on it's own? If it picks up, it's definitely a fuel problem.

I am also puzzled by sending out the ignition components for testing. I would be looking for another mechanic.

 

[HighTrim]

Re: 1994 evinrude 120 engine bogs out

Dont you hate those tanks that you cannot access, everytime I get one I end up putting in a latch so that I can repair them if need be.

I agree with Jim, get yourself a remote tank for testing and see if the problem dissapears, if it does, you know your onboard tank is the issue.

In reference to the carbs, there are multiple jets in carbs, for low, high, and sometimes mid range. So if a particular jet is clogged or varnished, sometimes only that particular range is affected.

 

[steve in va]

Re: 1994 evinrude 120 engine bogs out

i think a remote fuel tank is a great idea to try and i never have checked bulb or tried to push choke in to see if there was a change... you guys are great... also the motor is oil injected(vro) so if i hook a remote fuel source into the line past the vro that would also eliminate any vro problems as well right? so here's what I'm thinking... I'll get a six gallon tank.. and once it starts to run bad then I'll hook it into the line past vro and see if there is any change...but if i bypass the vro there will be no oil/fuel mix to motor so what amount of oil should i pour into a 6 gal tank to achieve to right ratio? i think the vro adds more oil as the the boat accelerates in relation to fuel consumption so i don't want a mixture that's too lean or too rich right? thanks again Steve

 

[ezeke]

Re: 1994 evinrude 120 engine bogs out

50:1 or 1 pint (16 ounces) for six US gallons.

You should have a OMS system on your motor that does not have the wide range of mixing that the old VRO had.

See the section called "Distinguishing VRO's" at the following thread:

http://continuouswave.com/whaler/reference/VRO.html

 

[wilde1j]

Re: 1994 evinrude 120 engine bogs out

Plug the remote tank in outside the motor and leave the OMS pump alone. If you by-pass the pump, there's no way to get fuel to the motor. The reason for the remote tank test is to make sure the fuel system on the suction side of the pump is OK. The pump gas output is tested with a pressure gauge.

 

[ezeke]

Re: 1994 evinrude 120 engine bogs out

If you are running a static test, elevate the portable tank; gravity still works.

 

[steve in va]

Re: 1994 evinrude 120 engine bogs out

ezeke, that link on the history of the vro was awesome!! i guess i need to check out oil tank too... also i don't know what i was thinking when i said i would bypass the vro... the point is to see if suction on fuel side is working (like Jim said) i can't wait to get the boat back from shop(still waiting on electronics test results) so i can work on it myself... i only wish i had found this forum before i took the boat in for service i now have a lot of things to try thanks to all of you... i just hope i can get it to malfunction so i can fix it

 

[steve in va]

Re: 1994 evinrude 120 engine bogs out

okay... well i didn't get my boat back yet but they did call and said "they think it might be the power pack" so just for peace of mind i am letting them put a new one on... i should get boat back next week and hopefully won't have anymore of the same problem but i will take my list of things to try with me just in case, for some strange reason i don't think thats what the problem is but i guess we'll see...has anyone ever had a powerpack go bad and do this sort of thing? steve

 

[wilde1j]

Re: 1994 evinrude 120 engine bogs out

I thought these hotshots sent all the ignition components out to be tested???

 

[kenmyfam]

Re: 1994 evinrude 120 engine bogs out

I thought these hotshots sent all the ignition components out to be tested???

Yes....I am a little worried about your "rocket scientists" that are taking care of you !!!!