1978 85hp Mercury hard to start

[Zoomworm1]

Motor is hard to start. This started at the end of last summer. I have drained the gas and replaced, replaced the fuel line/bulb from gas tank to motor, had the carbs rebuilt, replaced a couple of fuel lines on the motor, use new NGK sparkplugs, bought a new cranking battery in January and have it charged. To start the motor, I have to spray starting fluid into the carbs, and it will start. Once it is warm, it will start back up. The longer it sits, say thirty minutes it will take longer to start. I have to push the fast idle all the way up and usually use the choke.

I plan on getting a gauge to check the spark on the plugs. Could I have a compression problem? The plugs will have fuel on them, and there is fuel getting to the carbs. It as if the fuel does not fire.

When the motor is first cranked the boat does not idle well, but after you run down the lake, 3 or 4 minutes, put it in neutral, it will idle. The motor runs smooth.

The starter motor turns well, and does not have a flat spot. Is it possible that a starter does not send enough current?

I looking for help on what would cause the motor to not fire. I need to rule out the starter motor, fuel pump, compression in pistons, and the sparkplug wires/distributor. I use Mercury parts.

I can't buy a new motor, I have 2 kids going to the dentist to get braces. Thanks.

 

[jimlad]

Re: 1978 85hp Mercury hard to start

8) hi zoomworm1 welcome to iboats hang tight mate
one tip i would give you is not to spray starting fluid in to the carb 8)

 

[OldMercsRule]

Re: 1978 85hp Mercury hard to start

Hi Zoom, Welcome. Sounds like you may already know what to do. Jimlad is right about the starting fluid, (it does not have 2 cyl oil in it: so good way to torch a motor). Check compression #1, sounds like you have spark, (but the intensity could be an issue), fuel pumps/filters/lines next. Start with the easy cheap stuff first, then proceed until you find the problem. Good luck. JR

 

[tashasdaddy]

Re: 1978 85hp Mercury hard to start

this is how you start and inline Merc. pump bulb till hard, then give it 2 more really hard pumps, idle lever all the way up, hold choke, turn key 3 trys, pump hard again, hold choke for 1 try, should try to fire. these inlines like to be almost flooded on cold starts. very gas hungry, when cold. good battery and clean connections at battery and engine end.

 

[Laddies]

Re: 1978 85hp Mercury hard to start

First mercury did not make a 850 in 79, so without knowing which engine and ign system it is it's rather hard to trouble shoot
If the engine has a dist. then it's probably low voltage
If not then is't probably fuel related, lean low speed adjustment, low float levels or the chokes are not sealing well. the butterflys warped or are loose.
Even ADI engine have ign problems so it's very important to have the right model and engine to give advice, nothing beats the serail number as the 4 cyl 80 and 85 HP engines used 3 differant ign systems 3 or 4 differant powerheads and several differant carbs we need the correct engine ID