1989 Evinrude 100

[Chevelle74]

My 89 Evinrude has sluggish throttle when powering up. Change fuel filter and fuel lines from carbs to tank. New fuel too. When powering up if I depress the fuel primer in engine speed and power picks up. Also noticed when troubleshooting with muffs on the right side cylinders are hotter than left side. Also changed spark plugs. Still feel it's a fuel delivery issue. At this point I'm stuck. Thanks for any help.

 

[jakedaawg]

Rebuild carbs. But compression test this motor first.

 

[emdsapmgr]

Your engine has two thermostats, one for each head. It is possible that one of the two stats is stuck shut and may not be cooling that head properly. Check to see that your "hot horn" is functional. Also, use a laser temp gun to determine just what the head temps are. Normally at idle, the heads should run between 143 and 150. That's normal idle temps on that engine.

 

[Chevelle74]

After further troubleshooting and cleaning carbs this engine is now running normal temp and good throttle response. However in the process of troubleshooting I found that the pickup in fuel tanks do not seem to hold a prime in fact when I pressurize the ball I can hear backup back into tank and ball will not get hard. However if I disconnect pickup and put fuel line directly into the tank and pump up the ball gets hard and engine runs great. Cannot find any cracks in pickup tube. I'm confused. Why won't pickup allow to pressurize up system but yet I disconnect pickup and go directly into tank works fine. Confused

 

[emdsapmgr]

Are you running from a 6 gallon tank, or your boat's built in tank? If it's a loose 6-gallon tank, it's possible that the head of the tank has an air leak.

 

[Chevelle74]

The tanks are loose 10 gallon tanks made by tempo. The pickup tube is the swivel type and the size is approximately 1/2" I.D. Fuel line is 3/8" I.D. Also at pickup tube connection should there be a check valve? The pump ball has check valve.

 

[emdsapmgr]

Usually the larger 3/8" line is for the V6 engines and higher. No problem with using 3/8" on your 100. The only tanks I know that have a check valve are the built-in tanks that use an anti-siphon valve. Most of the cheaper Tempo tanks don't have a check valve. The fuel hose has two ball valves in the hose bulb. Usually these last a long time, but I've seen where one of the ball valves will fail, requiring replacement of the in line whole ball valve with a new one. Biggest problem I've encountered on these old plastic tanks is where the tank pickup gets a hole in it somewhere. Fuel below the hole won't get sucked up. Also, many times the plastic pickup is just pushed onto the tank head hose barb. With years of use, that seal where the fuel pickup meets the tank head will loosen up and permit air to get sucked up instead of fuel. You should be able to pump up the fuel hose bulb (hard) first thing each day. Once the engine is running, and the pump is sucking fuel, the bulb will soften and will run fine that way the rest of the day.

 

[Chevelle74]

I'm suspecting the problem is where the pickup tube meets the head cause your right about it just slipping onto the barb fitting. I'm thinking a hose clamp should correct that problem. Also I'll check the tube again for pin hole . I believe this is narrowed down to what we're discussing. I appreciate your help and I'll see what happens. Thanks again!!

 

[emdsapmgr]

A clamp to hold the pickup tube onto the head hose barb would be a good idea. I was working on a friends I/O boat. Had a "no fuel" problem too. Pulled the fuel pickup out of the tank head and found a Band-Aid crammed up the pickup. Completely plugged. A suprising find for sure!

 

[Chevelle74]

Lol!! Thats a first