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Results 1 to 22 of 22
  1. #1

    Default 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Hi, the title describes my problem. I've kind of concluded that it is a fuel problem, so I've changed tank and all fuel lines between tank and carburetors. No fuel leaks.

    I have the VRO-pump, and have just ordered a standard fuel pump. There seems to be a fitting for this on the port side behind the starter. There is 3 threaded holes, the middle hole has a bolt with a gasket in it. I guess this is the pressure/vacuum source for the standard pump?

    When I remove the VRO-pump, can I use this bolt to plug the pulse-line hole after removing the plastic fitting that is connected to the engine? Or should I leave the pulse line hose and plug it?

    Also, when i plugged the oil side of the VRO-pump, I realised that it was water instead of oil. I pumped out about 0.5 litres of water before any oil came from the tank. I then removed the oiltank, and tried running on premix. The engine smokes a lot more, but sounds better with 2% oil instead of 2% water, but it still stalls after about half a minute on idle.

    Question is, is it possible that water in the carburetors (from the oil tank) is causing the stall, instead of a faulty VRO-pump? Will the water be flushed out when running the engine, or do I need to drain the carburetors?

  2. #2
    Join Date
    Feb 2001
    Location
    Central West Florida
    Posts
    11,990

    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    (You) - I have the VRO-pump, and have just ordered a standard fuel pump. There seems to be a fitting for this on the port side behind the starter. There is 3 threaded holes, the middle hole has a bolt with a gasket in it. I guess this is the pressure/vacuum source for the standard pump?

    (Me) - Yes, that is the pressure/vaccum source for the regular fuel pump, as you suspect.

    (You) - When I remove the VRO-pump, can I use this bolt to plug the pulse-line hole after removing the plastic fitting that is connected to the engine? Or should I leave the pulse line hose and plug it?

    (Me) - Check to make sure that the threads are compatible first. Normally a brass fitting with a pipe thread is used to plug that VRO pressure/vaccum source hole. You could simply plug the line but it's best to install the fitting.

    (You) - Also, when i plugged the oil side of the VRO-pump, I realised that it was water instead of oil. I pumped out about 0.5 litres of water before any oil came from the tank. I then removed the oiltank, and tried running on premix. The engine smokes a lot more, but sounds better with 2% oil instead of 2% water, but it still stalls after about half a minute on idle.

    (Me) - That water problem entry into the oil tank has existed since day one back in 1984. You would think the engineers would have corrected it by now. One cannot leave that oil tank exposed to the elements without having rain or water spray enter it... and obviously to a great amount. Notice to all reading this.... Make sure that your oil tank is securely covered, out of the way of the elements (rain, spray, etc).... Keep the garden hose away from it when washing the rig down!

    (You) - Question is, is it possible that water in the carburetors (from the oil tank) is causing the stall, instead of a faulty VRO-pump? Will the water be flushed out when running the engine, or do I need to drain the carburetors?

    (Me) - Drain the carburetors to be on the safe side and pump a little fuel mixture thru them just to be sure that no water is lurking anywhere. It's unlikely that any water is there now BUT it's best to leave nothing to chance.

    Your problem sounds like the VRO has been damaged by the water problem which is understandable and common, and you are on the right track to doing away with it.

    I would add.... Check the compression to make sure that the water hasn't resulted in any internal damage such as piston scoring. Let us know what the PSI readings are on the individual cylinders.
    Our questions require answers. If you refuse to answer our questions, how can we answer yours?

  3. #3
    Join Date
    Sep 2010
    Location
    ontario
    Posts
    9,666

    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Water in VRO tanks is fairly commo.--Bought a matching pair of 90 HP motors that were damaged this way.------------Check compression imediately, and do not let motor sit with water inside ( possibly ) or there will be rapid corrosion on the crankshaft and bearings.-Get it running imediately!

  4. #4

    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Hi and thank you. The motor is easy to start, and runs good (until it runs out of fuel). Is it really necessary to test compression? Asking because I don't have the tool. Also I just bought the boat/engine and I don't want to find more problems... Regretting that I didn't test-run it in water before we sealed the deal... First time I have bought a boat, learning a lot...

  5. #5
    Join Date
    Sep 2010
    Location
    ontario
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    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Your best bet is to establish the condition of the motor !!----------A shop will do the compression test for a minimum fee.---------But a compression tester is about $40.00 and for anyone playing with outboards it is a good / best investment you will make.

  6. #6
    Join Date
    Feb 2001
    Location
    Central West Florida
    Posts
    11,990

    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Compression gauges are available in Wal*Mart, K-Mart, many stores besides automotive type stores. Shop around as you don't need the best unless you're going to be using it many times per day, every day.
    Our questions require answers. If you refuse to answer our questions, how can we answer yours?

  7. #7

    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Ok, I'll go buy the tool, can use it before I buy my next motor in any case . How is the procedure excactly?

    remove both plug lines, and mount tester instead of plug for the cylinder being tested, then run it on the starter (for how long)?

    Using a shop is best avoided as they charge 150-200$ an hour. (I'm in Norway).

  8. #8
    Join Date
    Sep 2010
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    ontario
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    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    I think I should move to NORWAY.--Then again they ran low on butter there last December. And what does a pint of beer cost at the pub.---------------Mix the gas and oil at 50:1 and use 40:1 if it is for hard work ( constant full throttle operation ) and you may enjoy that motor for a long time.

  9. #9

    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Quote Originally Posted by racerone View Post
    I think I should move to NORWAY.--Then again they ran low on butter there last December. And what does a pint of beer cost at the pub.---------------Mix the gas and oil at 50:1 and use 40:1 if it is for hard work ( constant full throttle operation ) and you may enjoy that motor for a long time.
    Unfortunately living costs are also high. A pint of beer in the pub is 15$+, a gallon of gas is around 10$, but we have cheap baby diapers for some reason. It's the only product being smuggled out of norway... Btw, butter supplies are back to normal.

    Is my above procedure for compression test correct?

  10. #10
    Join Date
    Sep 2010
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    ontario
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    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Yes that is how compression is checked.--------------You would have to get those rates for motor work , it is all relative I guess.----------I would work for $20 / hr if a beer was $1.50.

  11. #11

    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Also, what the customer is charged is not what the shop mecanic is paid.

  12. #12
    Join Date
    Sep 2010
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    ontario
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    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    We all know that.--------Sounds like there is a lot of " oil money " in Norway.---Driven the cost of everything way up.

  13. #13

    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Hi again, I've now tested the boat with the new non VRO-pump. The engine runs smooth, and the rev-counter shows 6000 at full speed. But I only get about 23 knots, it should do at least 30. Can i suspect the engine (compression etc.) or is it something else (propeller etc.) since get 6000 RPM? (I've bought a compression tester, but it's still unused as the boat is in the water).

  14. #14

    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    FYI, when stopping the engine, the rev-counter freezes between 1000 and 2000 RPM, a few knocks on the glass lowers the needle to 0. So maybe the 6000 isn't 6000?

  15. #15

    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    ...And the prop looks to good to be the original. What prop size should i shop for?

  16. #16
    Join Date
    Oct 2011
    Location
    maplevalley WA
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    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Confirm the RPM is correct. Have you actually had it to 30 knots and how are you measuring boat speed. You cannot judge performance with boat speed. Make sure the motor is running close to 100% as possible. Is the hull clean and trim correct then size the prop with engine rpm WOT with a light load. That is how fast it will go if you want faster get a bigger motor.

  17. #17
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    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    6000 seems a bit high to me 5500-5600 rpm sounds better what is spec for your motor. Find out what pitch prop you have if the rpm is correct go with a higher pitch prop to bring the rpm down to 5600rpm that will give you a little more kph also. You may get 30 knots if your boat is smaller than 16 feet.

  18. #18

    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Hi, yes, I just checked, WOT RPM should be 4500-5500. The boat is 15,5 feet. I just got the engine running after buying it, so haven't actually had it at 30 knots myself, but it has been tested at 31 knots (in a magazine) with a 50 hp tohatsu, so I should get more than 23 knots anyhow. I am thinking of ordering a 12x17 steel prop (the highest pitch option for my engine using a prop-finder). But maybe I should measure the one I have first...

  19. #19
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    Oct 2011
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    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    All I could find is your motor WOT rpm is 5000 rpm if your tach is correct it is way under propped increase the pitch at least 4. I was thinking you said the prop looked out of place. It is entirely possible someone didnt have the engine running good and tried to compensate by lowering the pitch. Confirm your tach is correct and spec WOT and size the prop from there.

  20. #20
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    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Cool that should get you closer to 30 kph. Try and get 5500 rpm with a light load and you will have plenty of power when loaded.

  21. #21

    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    Hi and thanks. How do I confirm my tach? Buy a new one?

  22. #22
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    Oct 2011
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    Default Re: 1993 50 HP 2 cyl Evinrude stalls, runs at idle when pumping gas

    I`v been working on that one maybe a timing light tach and multiply by two. You can use a VOM with Hz setting put a single lead out the pos terminal about 6 inches and put it close to a plug wire and then multiply the reading by 60. It worked on my truck I havent tried on a outboard yet.

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