check valves on intake manifold

peconicgreg

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Sep 26, 2017
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I have a 1984 evinrude 115hp. model number E115TXCRD. What I would like to know is if all of these engines have the check valves in the manifold for pressure equalization. I took what I thought was supposed to be a check valve out, and it was only a barb fitting. I ask because I am having an issue with my engine having a very bad hiccup when idling. From what I have read a bad check valve could cause this.
 

flyingscott

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Is this motor new to you? Are you running on muffs or the lake? The only valves in the intake are the reed valves and those are behind the carbs. The barb fitting may be for the reclaim line out of the airbox. I would look at your carbs and make sure they are clean as you possibly have a lean sneeze. A bad thermostat causing it to run cold could cause that. A spark plug wire being hooked on the hood when you put it on could cause that. Have you done a compression test.
 

peconicgreg

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the motor is fairly new to me. I purchased the boat last year. I used it twice at the end of the season. The barb that I mentioned in my first post was supposed to be a check valve, the other 3 barbs were check valves. I did a compression check and got 120s and 125s. I have found that one valve is very wet. I checked for spark on that cylinder and found it to be fine. the other issue I have is that the engine is very hard to start when cold. After running for a couple of minutes it will start up in one crank, still with the cough though. I also notice a very slight amount of fuel in the carb. barrels. Would faulty reed valves cause any of this. The engine is a 1984.
 

F_R

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Jul 7, 2006
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Parts book sez it has four check valves, part number 392988. That's all I know.
 

interalian

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Jul 23, 2009
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No Title

You'll have 4 brass check valves as seen on the silver manifold (from '82 model crossflow). The rubber hose you see is the silencer drain. 3 of the check valves are angled inward, the lowest one points straight forward. They should block flow in one direction.

The blue manifold is from a '79 motor that predates the drain system, but you can see the casting was 'ready' for them.
 

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Faztbullet

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It wont idle good on a hose...needs to be in lake/barrel with backpressure...
 

peconicgreg

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Sep 26, 2017
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doesn't idle well with muffs or in the water, it has that same cough. When I tried taking it out I couldn't get over 3000 rpm at wide open throttle. Previously it would rev. up to about 5000 rpm. at full throttle. I have cleaned the carbs thoroughly, tried running on an external fuel tank, installed new ignition coils and wires. all to no avail.
 

racerone

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Dec 28, 2013
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Compression test done recently ??----Oil injection in service ??----Are you pushing the key in while cranking it over when cold ?
 

peconicgreg

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Sep 26, 2017
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compression test just done, 120s and 125s. no oil injection, mix fuel. I am pushing in the key when trying to start. I checked to make sure the cold start solenoid is working and the knob is in the right position.
 

racerone

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Dec 28, 2013
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Pull the starter apart for cleaning and inspection.----Slow / marginal starter performance makes a motor " hard to start "
 
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