Merc 200 20 HP First time in the water in 15 years- 1 issue

[JGra]

Well I have been working on this boat for the last couple of month getting it ready for the water. Prior to this the rig sat for about 15 years under the shed. Everything with the boat did well. I only have 1 issue with the motor. the motor has a very good idle and starts very easy when its cold. The problem I am having is once you get past 1/4 throttle it will slowly die out and shut off. It will would crank right back up with a pump of the fuel bulb. I tried messing with the mixture screw while I was running but that did not make much differance. I think that maybe just for low speed mixture anyway. We just kinda made due with it for the day with running 1/4 throttle and trolling. It seemed to be running out of fuel to me. My son asked me why I had to pump the bulb to get it restarted. Jokeing he said we could just drive around pumping the bulb. I told him thats not a bad idea to try and see what happeneds. I got the boat on plane and started to give the bulb a light half pump about every 2 seconds while I throttled up. It ran GREAT!!!. I never skipped a beat. This tells me it is indead running out of fuel. Before taking it out I went thru the motor by rebuilding the fuel pump, replacing the fuel lines that looked bad. Took the carb off and apart and cleaned all the passages and reassembled. Replaced the water pump, shif shaft seal, and prop seals. Also replaced all the rotted wiriring under the cowl. I did have the tank vent open but could it be the bulb? The tank has also sat for the 15 years but I did not do anything to it. Do I need to replace all the fuel lines?, even the ones that look good. Does the carb need to come back off. I did not really notice this prior to going out due to not running it up to high in gear on the Hose. I was told that is bad for the motor. Is that true. Really sorry for the long post but I like to give as much info as I can

 

[j_martin]

Re: Merc 200 20 HP First time in the water in 15 years- 1 issue

At 15 years, even a good looking fuel line is likely bad inside. A tank that has been sitting for 15 years has to have either flakes of varnish formed from old fuel, or rust in it.

Sounds like your good work got hosed by failure to do all the cleaning required. Odds are the carb has debris in it.

hope it helps
John

 

[JGra]

Re: Merc 200 20 HP First time in the water in 15 years- 1 issue

Well I think I may have found it. The main fuel line from the fuel pump to the carb was in bad shape when I started the project. This hose had crimped on ends on it. I could not find an OEM so I had to make one. When I pulled the cowl it looks like the fuel line is kinked where is makes its turn to go to the carb. On bending a spare piece and kinking it while blowing air thru it looks like about half the volume is being blocked. Dont know if this is my problem or not. I was only having to give it a 1/4 to 1/2 light pump on the bulb about every 2-3 seconds to get it to run wide open with no problem. Going to rework the fuel line and give

 

[JGra]

Re: Merc 200 20 HP First time in the water in 15 years- 1 issue

Well I fixed the kinked fuel line and I replcaed all the other fuel lines and cleaned everything again. I put it on the muffs and brought it up just past 1/4 throttle and she dies after about 5 seconds. I have been suspecting the fuel tank and bulb as having a problem so I disconnected it from the end and squeezed the bulb and it would dribble fuel out the end and the bulb would never get hard. I hooked it back up to the motor and took the cowl off and started squeezing the bulb and heard a hissing noise. After looking around fuel was pooring out from around the fuel hose conector where it mates to the connector on the eng. I see there is an O RING in there that looks likes its swelled up. Could this be my problem. I know these carbs draw fuel from the tank and if this is not sealing could this be my high speed fuel loss. I am going to replace the fuel line, bulb and fitting and hope for the best.