Engine is extremely hard to start but runs great once it kicks over

[Surfersteve]

I have a 1976 Mercury Marine 4 cyl outboard (4 cycle) engine thatI just rebuilt and had to replace all bearing and 2 of 4 pistons. It is still hard to get started, but once it does after cranking for 2 to 3 min and priming the you know what out of it it will start to sputter and then kick on. I am choking it manually and the fuel pump was just rebuilt. Once she gets going she runs great without falter. Carbs have all been rebuilt and have been tunes, Spark is strong to all four cylinders. After I get it going and shut it off I can start it back up no problem as long as its within a min or two. After 3 or four min it is a pain to get running again. I am thinking I am having a vacuum problem in the primer bulb it is old. I am an going to bass pro now to get a new one. Any ideas will be great

 

[Surfersteve]

Re: Engine is extremely hard to start but runs great once it kicks over

Sorry about all the typos in my post, I am in a quite a hurry.

 

[timmathis]

Re: Engine is extremely hard to start but runs great once it kicks over

Make sure that motor is all the way down to start.<br />good battery and geting fuel. Tim

 

[Clams Canino]

Re: Engine is extremely hard to start but runs great once it kicks over

What Tim said - and it's a two stroke, 4 cylinder.<br /><br />No 4 strokes (cycle) made by Merc then.<br /><br />-W

 

[Surfersteve]

Re: Engine is extremely hard to start but runs great once it kicks over

Thanks guys, I just realized I said it was a 4 stroke when your right indeed its a 2 stroke. It has a great battery and alot of fuel but it seems as if only carb number one of two is spraying fuel from its nozzle. No clogs in lines. What might cause this carb to be bad. I have torn it down, not all the way, but the float and needle valve seem to be in check. What else can I do to the carb. I have cleared all the lines in the carbs. When I squeeze the primer bulb is it suppose to spray fuel out????? Please help<br />Thank you Steven Atkins

 

[Bob H.]

Re: Engine is extremely hard to start but runs great once it kicks over

Fuel shouldn't come out when you're squeezing the bulb. The purpose of the bulb is to initially fill the carb bowls. Sounds like the check valve in the bulb is stuck open. Also clean the choke circuit in the bad carb. A proper tear down and cleaning of the carbs wouldn't hurt.

 

[timmathis]

Re: Engine is extremely hard to start but runs great once it kicks over

Steven don't worry about typos. 1/2 of us out here can't type or spell! but we seem to get the job done. Clean carb if you need to and I would recheck timing. Good Luck, Tim

 

[Chinewalker]

Re: Engine is extremely hard to start but runs great once it kicks over

Fairly common issue with a lot of Mercs - the choke tends to not shut all the way either through wear or adjustment. Make sure the choke butterflies are closing fully. As a test, try stuffing a rag in both carbs and then try starting it. If it kicks off easily, then it's definitely the chokes...<br /><br />- Scott

 

[Surfersteve]

Re: Engine is extremely hard to start but runs great once it kicks over

Ok, After taking a closer look, when I do get it running both carbs are indeed working, the top seems perfect the bottom sputtering fuel a bit more. When I stick my hand over either carb inlet the engine starts to slow so i know they are operating. When cold starting the engine turns and turns for a min or two then starts kicking slightly, the starter disengages but doesnt quite get going. I am about to pull the carbs off and check on the choke issue, I do appreciate everyones help, your are all such great people

 

[Surfersteve]

Re: Engine is extremely hard to start but runs great once it kicks over

Well I gave the carbs a complete teardown and they didnt seems to bad at all, once back in still didnt start, so i put some gas in a spray bottle and gave her a squirt while trying to kick her over and voila........... she kicked over and ran great, did the same and she flew through the water . Cylinder one has a brand new piston and rings in which the mech fuel pump gets its power from, the pump was rebuilt. Does cyl one have to be broken in, in order for the pump to run correctly. I know quite a bit about engines but when i put the rings on the piston, should they have stayed loose or be tight and then loosen up after the engine is broken in ?????????????Please help

 

[timmathis]

Re: Engine is extremely hard to start but runs great once it kicks over

When starting give the bulb 2 or 3 extra hard pumps and it should help it start. Don't worry you can't hardly flood a old merc. Also be sure to use pre mix in the spray bottle. Tim

 

[swist]

Re: Engine is extremely hard to start but runs great once it kicks over

I don't know anything specific about this engine, but hard starting followed by running fine could also be a crankcase pressure problem - a leak in a gasket which does not allow the crankcase to develop sufficient vacuum could be the culprit. Also things like loose/cracked piston rings....<br /><br />Also I think the choke may be a red herring. An engine shut off for only 3 or 4 minutes should not get cold enough to need choking to start.

 

[LubeDude]

Re: Engine is extremely hard to start but runs great once it kicks over

Originally posted by Steven Atkins:<br />[QBthe bottom sputtering fuel a bit more. [/QB]

If its actually spraying fuel back out of the carb, even a little, you have bad reeds. That alone will cause hard starting.

 

[timmathis]

Re: Engine is extremely hard to start but runs great once it kicks over

Have you checked your plugs? Sometimes break in will foul them a little. You can clean them. That may help some.