1983 175 Evenrude Fuel Problem

[jwmullins79]

I thank all of those who helped me with my last problem on my little 55hp engine. Now I gotta bigger problem with my 175.

This engine has been sittin up for a few years, and I aquired it for almost nothing. Put a little bit of work into it, and got it runnin. HOWEVER, I have a major problem in the fuel system somewhere. After gettin the engine running, and taking it out for a test run, I quickly found out that that I wasn't getting all the power I should out of this engine. Seemed like it wasn't running on all cylinders. I got it home, took the spark plugs back out of it, and checked all cylinders for compression again. Compression is good. Noticed though that the top right cylinder (looking at the engine from the back of it) is dry. Hasn't been getting fuel/oil mixture to this cylinder. All other cylinders and spark plugs have a small oil residue on them, this one is as dry as it can be.

What is my problem here? I'm thinking a clogged jet, or a broken reed valve. Any help would be appriciated.

 

[The-Machinist]

Re: 1983 175 Evenrude Fuel Problem

I would start by rebuilding all carbs. The dry cyl. is a death sentence: No fuel=No lubrication.

 

[tashasdaddy]

Re: 1983 175 Evenrude Fuel Problem

this applys to all motors. http://forums.iboats.com/showthread.php?t=158086

this for carbs. http://forums.iboats.com/showthread.php?t=244013

 

[jwmullins79]

Re: 1983 175 Evenrude Fuel Problem

I would start by rebuilding all carbs. The dry cyl. is a death sentence: No fuel=No lubrication.

Yea, I know. As far as I can tell at the moment, I haven't killed it yet. Caught it in time, still have good compression, and don't look like I've scored the walls much at all. Should be alright once I get this fuel/oil problem figured out. Thanks.

this applys to all motors. http://forums.iboats.com/showthread.php?t=158086

this for carbs. http://forums.iboats.com/showthread.php?t=244013

I thank ya Tashdaddy, I'd seen both of these threads already, and they are great threads with lots of info. Was just wonderin if anyone had already had this exact problem to keep from havin to keep diggin. Am goin outside now to tinker with it, and see if I can figure out what's goin on, or better yet not goin on.

 

[ezeke]

Re: 1983 175 Evenrude Fuel Problem

With a broken reed the mix will be coughing back through the carburetor.

Since cylinder #2 is not having the problem the high speed jet on cylinder 1 is probably clogged. The jets lie at the bottom of the float bowls where they pick up all of the junk from the fuel system as well as any gel from old fuel sitting there.

You could have air leaking between the intake manifold and the carburetor which would prevent the piston from pulling the fuel through. Make sure that the carburetor bolts are tight.

The high speed jets are aligned with and directly behind the drain plugs, so you can drain the bowls and flush the bowls with a little pressure on the primer bulb if you take the drain plugs out.

 

[jwmullins79]

Re: 1983 175 Evenrude Fuel Problem

With a broken reed the mix will be coughing back through the carburetor.

Since cylinder #2 is not having the problem the high speed jet on cylinder 1 is probably clogged. The jets lie at the bottom of the float bowls where they pick up all of the junk from the fuel system as well as any gel from old fuel sitting there.

You could have air leaking between the intake manifold and the carburetor which would prevent the piston from pulling the fuel through. Make sure that the carburetor bolts are tight.

The high speed jets are aligned with and directly behind the drain plugs, so you can drain the bowls and flush the bowls with a little pressure on the primer bulb if you take the drain plugs out.

I believe I have several problems working against me all at the same time. I have takin the carb off, and cleaned it out. Making sure all jets are free of obstruction, and all orafices are clean and free flowing. After reinstalling the carb, and starting the engine, I ran into another problem. My fuel primer bulb is collapsing while the engine is running. I have a fuel water seperator filter onboard, and am goin to the store right now to purchase a new one to ensure that's not plugged up. Only other thing I can think of as far as the bulb collapsing is that the fuel line has plugged up where it connects to the fuel tank. Am going to try the filter first. Should take care of it. Thought of the primer bulb being bad, but put a new one on and did the same thing. Will let everyone know the results after I get back. Thanks again for the help.

 

[ezeke]

Re: 1983 175 Evenrude Fuel Problem

Your anti-siphon valve may be the problem. It is located at the tank inside the outgoing hose fitting connection and on most tanks consists of a spring and ball bearing. They are easily clogged.

 

[jwmullins79]

Re: 1983 175 Evenrude Fuel Problem

Your anti-siphon valve may be the problem. It is located at the tank inside the outgoing hose fitting connection and on most tanks consists of a spring and ball bearing. They are easily clogged.

This is the next step in my process. I changed the fuel/water separator filter I have installed but to no avail. I'm goin to check into the check valve in the fuel line. I didn't realize that there was one on this boat. I was thinkin bout maybe a screen where the fuel line connects to the tank. Don't know if I could back feed air into the system to try to clear the line or not. Have to take the center console out, then the floor panels underneith it to get to the fuel tank.

 

[tashasdaddy]

Re: 1983 175 Evenrude Fuel Problem

vent on fuel tank could be clogged, kritters love to get into them.

 

[Silvertip]

Re: 1983 175 Evenrude Fuel Problem

A primer bulb going flat indicates a fuel restriction between the bulb and end of the pickup tube in the tank. But that will not affect one cylinder. It's a separate issue.

 

[jwmullins79]

Re: 1983 175 Evenrude Fuel Problem

vent on fuel tank could be clogged, kritters love to get into them.

I checked the vent line, and it's clear. Thought a dirt dobber had gotten in there or something. But luckily it hadn't.

A primer bulb going flat indicates a fuel restriction between the bulb and end of the pickup tube in the tank. But that will not affect one cylinder. It's a separate issue.

I realize that it's a separate issue, sorry for the confusion, I got fuel up to all the cylinders now. I believe it's several issues I got, they are just surfacing one at a time as I eliminate other options. I am goin to check into it next week when I get time to tinker on it again. I do thank everyone for all their help and advice while I mess with this thing.