Hard Starting Outboard Motor?

Question

I have an 1974 85HP Johnson that is very difficult to start. Just had it tuned up and still have a difficult time starting when in the water. When on dry land with the ear muffs on, a couple of seconds worth of cranking and brooooommmm! No worries. It fires right up without so much as a burp. But put that thing in a lake and I crank it for ten minutes or so to get it going. At first it will act like there is no fuel or spark, then it will act like it wants to start and then I'll get 2-3 seconds of running but then it quits. Then nothing. Then I may get 3-5 seconds of running. Then nothing. But after a while it will finally fire up and go.

Any ideas? Is it afraid of the water?

Answer 1

Be sure the engine it all the way in the down position when you start it on the water. I know sounds too easy right, try it though if you have been trying to start it with the engine tilted up. That should solve it for you.

Answer 2

My 84 Mariner 40 horse did the same thing with the muffs it would run great! on the water nope, not gonna happen.

Look to your fuel pump, i'm not sayin that's the prob but its as likely a place to start as any

Answer 3

When not in the water the engine is not "under load", ie not doing any work.  Although strictly speaking it is still not doing any more work when cranking in the water, as it is only trying to pump cooling water through the engine......

So, here is something  for you to consider:

Assuming that timing etc has been set correctly by who-ever tuned the engine and no schoolboy errors have occurred with the kill cord, it will start easily enough on dry land when not under load and even rev up happily as well.

The only difference with running it on dry land with ear muffs and in water is the fact that the leg is submerged and the exhaust gases are having to be pushed down the leg and out through the water.  

Now it is possible for even a worn engine to start when not "under load", but a worn engine might prove to be troublesome if there is a greater restriction (ie water) in the exhaust system.  Once the engine is at working temperature, the expansion in the metal parts may be sufficient to take up the tolerances allowing the engine to run.

Tuning engines entails servicing air filters, carburretors and setting the timing mechanically and electrically.  However, engines are not made of glass so you cannot see what is going on inside them.

A good indication of the state of your engine is to carry out a compression test.  This is quite simple to do yourself and you will not need to go out and pay a mechanic!

This will only take about half an hour including the time it takes to set up the test.

All you need to know is the compression data for your engine, ie how many bar, lbs/ft.ins that you will expect to see on the test guage.

In case you do not already know, here is how to do the test:

1) Nip down to your local Tool Mart and hire a petrol compression tester for the day.

This will consist of a pressure guage, a short length of high pressure hose and/or metal pipe with a built in pressure release valve and a rubber bung or spacer on the end.

2) ENSURE GEARBOX IS IN NEUTRAL AND YOU ARE NEVER IN A POSITION WHERE YOU COULD BE TANGLED IN THE PROP!!!!!

3) Prepare the engine for test by removing the source of fuel and the spark plugs.

4) Tie the HT leads (spark plug leads) up out of the way (remebering which cylinder they belong to), so that they are well away from the now open cylinders and any other metal to prevent a spark from occurring.

5) Ensure the test guage reads "Zero" by pushing and releasing the pressure relief valve on the compression tester.

6) Push the tester firmly into one of the spark plug holes and hold it there.

7) Get a happy helper to crank the engine for you while you are at the buisness end for up to 10-15 seconds.  Carry out the test 3 times to obtain an average result for each cylinder, remembering to reset the test guage to Zero each time, also ensuring you wait for 30 seconds between each cranking of the engine so as not to overheat the starter motor.  Make a note of the result in bar, lbs/ft.ins and repeat the test for the remaining cylinders.

8) Carry out the same test again for each cylinder but this time squirt a small ammount of oil into each cylinder in turn.  If the results show a great increase in pressure this will indicate worn piston rings.

Compare the results between all of the cylinders.  If the results are all roughly the same but significantly lower than the expected result then you will be looking at a top end overhaul.  If there is a significant difference between one or more cylinders this will indcate a more serious condition in wear in the engine.

Good luck!

Answer 4

hi there....

Ok.. theres a couple of things this could be..

The worse case is that its the compression in the cylinders... if its low then it cannot push the exhaust out of the cylinders.... hence hard start...

However......  I had a similar problem....   I have a 1972  50hp

and it took me a month to finall get to the bottom of it...

Ok.   beleive it or not...  its most probabily a carb problem..  you may have to ajust the idle on your carbs....  to increas the revs...  yes it will start well on muffs becasue its not under pressure.. but on the water its different....

Also check your coils to make sure you dont have a cracked coil..  both my coils were cracked meaning it only ran on one cylinder at a time..  so it sounded  ok on liand but in the water it was hard to start..

Finally look under the fly weel and see if your stator is melting ...  I also had that problem..

Mine ran great  after i sorted out the carbs but then i found the cracked coils and the stator went bad....

But now it runs like a new motor...

feel free to email me  with any questions..   But I am leading towards it being the carb and the motor only running on one cylinder.

Answer 5

Hi There

Mate it seems as though everyone on the page is right on que. Just follow through the steps of checking cracks in coils, spark compression etc. and all these will put you on the right track to properly diognosing your troubles.

      Hats off to all ppl. who answered.

                     Hope these will help you out

Answer 6

It sounds as if the gas is not getting through to the carb when you're on the lake.  Make sure you prime the carb really well by pumping the rubber bulb in the gas supply line before you crank it,  if that's the type of tank you use. Also, if it's fitted with a choke, make sure you use it.  Some of them need the choke even on a warm day.  You could also encourage it by giving it a shot of "cold start" (ethyl ether).

  Make sure the spark plugs are the correct heat range.

  Check the coil(s).

Answer 7

Sounds like the crankcase is leaking.

A two cycle engine must have a tightly sealed crankcase to start and run right, as the downward stroke of the piston forces the fuel/oil mixture up into the engine for the compression and firing stroke.

  After the engine warms up, sometimes they will run, but only after a hard start.

  A re-sealing might be necessary and that will include a complete tear down, and the possible replacement of the shaft bearings, upper and lower, and all gaskets.