1983 mercury 90hp starting problems i think its fuel

[chadweiser]

My grandfather has a 1983 mercury 90hp with the gold stripe on it. Well if the boat sits longer then a week it wont start at all until you spray gas in the carbs. once it starts up and runs. it will start as soon as you hit the key. the choke is working. I pumped the ball everytime until tight. it only does it when the boat sits longer then a week. like if i go out there the day after running it. I would pump the ball, pump the throttle a few time, and hit the choke and it will start. please let me know what you think.

 

[oldman570]

Re: 1983 mercury 90hp starting problems i think its fuel

Try putting some Sea Foam gas treatment in the gas and run the motor for awhile. If it dosen't help you'll have to rebuild the fuel pump and carbs as ethonal gas is bad on older gaskets and rubber lines.
Oldman570

 

[Chris1956]

Re: 1983 mercury 90hp starting problems i think its fuel

Chad, Those old inline sixes were known for hard cold starting. What shape are the battery cables and the battery in? If the starter spins too slow, it makes it hard to start. Make sure the motor is all the way tilted down. Hold down the choke button and crank her, cold start lever all the way up. Crank until she fires, with the choke on.

Oldman had given good advice for carb clogs. Carb clogs do not affect starting, unless they are really bad, and then spraying fuel into the motor doesn't cure it. I would therefore wait on doing that. Check the fuel filter for evidence of fuel line breakdown.

 

[chadweiser]

Re: 1983 mercury 90hp starting problems i think its fuel

hi chris and oldman570, this boat doesnt have a cold start lever. Also the fuel line is new. Im going to try sea foam and the carbs where rebuilt a year ago. He has only ran ethonal in it once and it was only a few gallons. since then it has been kept with fresh non ethonal gas. Im thinking oldman might be right on the fuel pump needing rebuild. once it fires up, it can sit for a 5-6 hours and that afternoon go bump the key and it fires right up.

 

[strokersquid]

Re: 1983 mercury 90hp starting problems i think its fuel

sounds like the fuel evaporates from the carbs after sitting a long time, which is to be expected. Then more priming is necessary to get fuel in the carb bowls and ultimately into the cylinders. Do you run the motor out of fuel when storing or not ? If the pilot jets are clogged, then fuel would help to start but it would die unless throttled. I have a 1993 100 HP and I need to use starter fluid to start if it sits a week.

 

[Chris1956]

Re: 1983 mercury 90hp starting problems i think its fuel

OK, No cold start lever. Does the control have a throttle only setting? You do need to advance the throttle for cold starting. Also choke the daylights out of it when cold starting.

 

[Chris1956]

Re: 1983 mercury 90hp starting problems i think its fuel

The problem is not ethanol, and it is not the fuel pump.....

 

[chadweiser]

Re: 1983 mercury 90hp starting problems i think its fuel

It will idle in neutral after the motor has started. I dont run it out of fuel always keep 1/4 of tank or more. I have a clear glass inline fuel filter about a foot from where the fuel line enters the engine. I prime the ball until it is hard and the filter is completely full of gas.

once i let it sit for about two and half weeks. I had to hold the choke and pump the throttle rapidly, it finally would start. It took awhile. Im sure if i sprayed fuel in the engine that time it would have started.

sounds like the fuel evaporates from the carbs after sitting a long time, which is to be expected. Then more priming is necessary to get fuel in the carb bowls and ultimately into the cylinders. Do you run the motor out of fuel when storing or not ? If the pilot jets are clogged, then fuel would help to start but it would die unless throttled. I have a 1993 100 HP and I need to use starter fluid to start if it sits a week.

 

[phebus1]

Re: 1983 mercury 90hp starting problems i think its fuel

Pumping the throttle will not help you. There is no accelerator pump in the carb.

 

[Lone Duck]

Re: 1983 mercury 90hp starting problems i think its fuel

sounds like the fuel evaporates from the carbs after sitting a long time, which is to be expected. Then more priming is necessary to get fuel in the carb bowls and ultimately into the cylinders. Do you run the motor out of fuel when storing or not ? If the pilot jets are clogged, then fuel would help to start but it would die unless throttled. I have a 1993 100 HP and I need to use starter fluid to start if it sits a week.

Starter fluid is very hard on outboards. Use fuel instead.

 

[oldman570]

Re: 1983 mercury 90hp starting problems i think its fuel

Chris is right on your problem. See if there is a square button on the control near the povit center of the lever. You can push it in and at the same time move the lever forward or if you can push the lever sidways toward the center of the boat and forward. It should act as the fast idle without the motor being in gear. Only push the leaver a short distance till you find where the motor will start and run at a fast idle, say 1200RPM. Be ready to chock it every now and then as it will want to die till it is warmed up. Never use starter fuild as it could damage the bearings, rings, and pistons because of the lack of oil.
Oldman570

 

[strokersquid]

Re: 1983 mercury 90hp starting problems i think its fuel

mine has a push button on the throttle pivot. is that what you mean ?

 

[Chris1956]

Re: 1983 mercury 90hp starting problems i think its fuel

The "Throttle only" function is activated by a push button on many controls. On others you need to pull the throttle handle straight out a bit. There are probably other controls that do it other ways.