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Page 2 of 2 FirstFirst 12
Results 31 to 47 of 47
  1. #31
    Join Date
    Dec 2006
    Location
    Mount Dora, FL, USA
    Posts
    20

    Default Hello Joe: I built spark test

    Hello Joe:
    I built spark tester as instructed and tested spark. I have good blue spark on both clyinders.

  2. #32
    Join Date
    Feb 2001
    Location
    Central West Florida
    Posts
    12,018

    Default "David.... Your most recent po

    "David.... Your most recent post above (top plug and it is dry as a bone) indicates that either the top carburetor is malfunctioning in some manner such as, no fuel entering float chamber, high speed jet completely clogged, or the slow speed adjustable needle valve misadjusted or obstructed....OR

    That top reed plate assembly (leaf valve) has either a leaf broken or something is holding a leaf open....OR

    A hole exists in the top section of the crankcase (which would be pretty obvious).

    I doubt the hole in the crankase senario so I'd suggest you double check the other areas mentioned. If compression and ignition (spark) are as they should be, that leaves only a fuel problem which apparently pertains to the top cylinder only.

    Let us know what you find."
    Our questions require answers. If you refuse to answer our questions, how can we answer yours?

  3. #33
    Join Date
    Dec 2006
    Location
    Mount Dora, FL, USA
    Posts
    20

    Default "Hello Joe: AT ONE POINT WE S

    "Hello Joe:
    AT ONE POINT WE SWAPPED CARBS, BOTTOM ON TOP AND VICE-VERSA. STILL RAN ON BOTTOM CLYINDER. WHEN I HAD INTAKE MANIFOLD OFF I SWAPPED LEAF VALVE ASSEMBLIES, TOP TO BOTTOM AND BOTTOM ON TOP. STILL NO HELP. LEAF VALVES LOOKED GOOD. I EVEN REPLACED THE GASKETS WHEN I HAD INTAKE MANIFOLD OFF ENGINE. I WILL TRY AND GET THE FLYWHEEL OFF. IF THERE IS A CRACK IT MIGHT BE UNDER SAME. WILL ADVISE WHEN I GET IT OFF. THANKS FOR YOUR ASSISTANCE"

  4. #34
    Join Date
    Feb 2001
    Location
    Central West Florida
    Posts
    12,018

    Default "Too bad you don't live in

    "Too bad you don't live in thia area. That's a engine I'd really like to lok at. You've just about covered all the bases as far as I'm concerned according to the info in your last post.

    The only other thing I can think of at the moment is a possible completely clogged fuel line leading to that top carburetor.

    A hole anywhere, even under the flywheel, should have the fuel/oil mixture flying about everywhere.

    Morten.... Anything else you can think of?"
    Our questions require answers. If you refuse to answer our questions, how can we answer yours?

  5. #35
    Join Date
    Apr 2006
    Location
    , Langkawi, Malaysia
    Posts
    5,750

    Default "Puzzels me as it puzzels You

    "Puzzels me as it puzzels You Joe.
    Normally a dry plug indicates it is working, he did not say if it was any color on it, or still as new compared to the other one.
    Wet plug normally indicates fuel, but unconplete/lean combustion.
    If the cylinder is dry as well, I fear some serious dammage after all the testing. It was mentioned that the head was to be dismantled, was it?
    Then comes the blow back symptom. I have no parts available and no engine, just the parts pcs from BRP. If the leaf valves are sealing properly, the blow back must come from somewhere else. On the part pic of the intake manifold at the leaf plate next to pos marker '3' there is a hole indicated that is not for a screw. I think to remember that some plates have a small fiber valve/screen installed. Might that be missing here?
    A hole in the cranck case without visible leakage sounds odd, even a leaking cranck shaft seal. It would normally create some oil/fuel leakage traces.
    What happends if some fuel-oil mix or fogging oil is squirted into the carb throat when running? any changes?
    lots of questions but no direct answers.
    "

  6. #36
    Join Date
    Feb 2001
    Location
    Central West Florida
    Posts
    12,018

    Default "If the intake/reed gasket was

    "If the intake/reed gasket was faulty, that would explain the blowback and no top cylinder response.

    I agree a normal firing plug would be a somewhat dry plug BUT is that plug a dry NEW looking plug or a light brown plug, fluffy black dry plug, what exactly does it look like?"
    Our questions require answers. If you refuse to answer our questions, how can we answer yours?

  7. #37
    Join Date
    Dec 2006
    Location
    Mount Dora, FL, USA
    Posts
    20

    Default Will try and answer some of yo

    Will try and answer some of your questions gentlemen.
    Joe: I replaced fuel line between carbs with a new line a month ago.
    Morten: In answer to your question on spark plug. New plug still in new condition after running engine. No sign of fuel ever reaching combustion chamber. I have not removed the head at this time.
    Blowback problem was solved when I replaced manifold gasket with new gasket. I did squirt some seafoam into throat of top carb as engine was running. It did make a difference in the way engine sounded. Today I will squirt some fuel/oil mix into top carb with engine running and get back to you guys with the results. I don't have a tach.

  8. #38
    Join Date
    Feb 2001
    Location
    Central West Florida
    Posts
    12,018

    Default "David.... The spark plug appe

    "David.... The spark plug appearance of still looking new and clean absolutely indiates that no fuel is reaching that combustion chamber.

    Assuming that fuel is present in the float chamber which would be obvious if the lower front screw/bolt plug is removed from the float chamber, I can only suspect the following.

    In Mortens post of December 30 above, a exploded view of a carburetor is inserted. The high speed jet is located and pictured at the lower center portion of the float chamber. Fuel must flow thru that jet before it has access to any other fuel passageway. Check to make sure that it is clear of any obstruction. A clogged, gummed, fouled jet is a permanent shut off valve."
    Our questions require answers. If you refuse to answer our questions, how can we answer yours?

  9. #39
    Join Date
    Dec 2006
    Location
    Mount Dora, FL, USA
    Posts
    20

    Default Joe: I swapped carbs on one o

    Joe:
    I swapped carbs on one of my previous posts. Top carb in bottom position and moved bottom carb to top position. Still ran on bottom clyinder only.

  10. #40
    Join Date
    Feb 2001
    Location
    Central West Florida
    Posts
    12,018

    Default "If with the engine running, a

    "If with the engine running, and you cover the top carburetor throat partially or fully, do you feel any suction, and does the engine pick up and fire on that cylinder when you do this?"
    Our questions require answers. If you refuse to answer our questions, how can we answer yours?

  11. #41
    Join Date
    Apr 2006
    Location
    , Langkawi, Malaysia
    Posts
    5,750

    Default "Was the carbs rebuild with ne

    "Was the carbs rebuild with new gaskets? Gasket 39 on the carb pic is very often a problem maker - too 'thin' or cracked.
    Secondly if You run at the starter with choke closed, does fuel almost pour out of the carb throats?
    Could You make a test by bypassing the fuel pump and put the fuel line straight onto the carb and use the bulb as manual pump?"

  12. #42
    Join Date
    Dec 2006
    Location
    Mount Dora, FL, USA
    Posts
    20

    Default "Have some success with your s

    "Have some success with your suggestions gentlemen. I used starter to spin engine with spark plugs out and put my fingers over the carb throats one at a time. It appears that the bottom clyinder has a little bit more suction than the top one. I spun engine with full choke, gas ran out of the throats of both carbs. This test was before I eliminated the fuel pump. Then I hooked gas line directly to carbs and used bulb as a pump and started engine. Engine still runs rough although top clyinder now appears to be firing. When I pulled the top new spark plug it was wet for the first time. Something still not right. Adjusting slow speed adjustment screws did not seem to help make engine run smother. I need a timing light to check the timing. So many people worked on this engine before me I might find just about anything wrong. I discovered this morning that the throttle plate linkage between the carbs was out of adjustment. With top throttle plate closed the bottom was about one third open. Hard to say how long it has been, maybe years since this engine ran properly. With engine running, both carb throats have strong suction. I am now convinced that I do not have a cracked block. Joe,Morten, the timing and the carbs may be the remainder of my problem. The former owner told me he took this engine to a dealer 2 years ago and had the carbs rebuilt because engine was not running properly. When he got it back he noted no improvement. Recently, my friend disassembled the carbs and noted needle valves showed no wear so were probaly recently rebuilt. There was corrosion and other gunk in carbs. because engine had not run in 2 years, The fuel in the fuel tank looked like green mud. I tossed the tank and purchased a new fuel tank. He cleaned the carbs up as best he could with no air commpressor and put them back together with the old gaskets. I believe we are on the right track to getting this engine running properly. I will order new carb kits. I will be traveling to North Carolina the first week of February to pick up my tools. I have an air compressor so I can properly clean carbs and blow out all passages. I also have a timing light. When I first started this project I had blowback on top clyinder. Turned out to be leaking intake manifold gasket. I did not have proper spark. After running tests I narrowed it down to the power pack. Replaced same and now have good spark. I wonder? is it unusual to find this many things wrong with an engine at the same time? Without you guys giving me advice and telling me how to run these tests I wouldn't have made any progress at all. Thanks again guys. I will continue to keep you all informed of my progress, or lack of. After rebuilding carbs with new gasket and checking the timing I will get back to you with the results."

  13. #43
    Join Date
    Dec 2006
    Location
    Mount Dora, FL, USA
    Posts
    20

    Default "I just remembered something e

    "I just remembered something else guys. When engine is running at about 3000 rpm, I'm guessing as I don't have a tach, engine sounds as if top carb is kicking in and out. By that I mean engine will be running rough and then it will smooth out and then run rough then smooth. Acts as if fuel is being turned on and off to top carb?"

  14. #44
    Join Date
    Apr 2006
    Location
    , Langkawi, Malaysia
    Posts
    5,750

    Default "In an old 'preowned'

    "In an old 'preowned' engine like this You may be prepared to find almost everything!!! Particularly if the previous owner(s) have not been in possession of a proper manual when working on it!"

  15. #45
    Join Date
    Feb 2007
    Location
    SurfCity, NJ, USA
    Posts
    2

    Default I am looking at buying a boat

    I am looking at buying a boat with a 1998 johnson 175 outboard. What should the compression read on this engine. What else should I check to get a good idea if this engine is in descent shape?

  16. #46
    Join Date
    Dec 2006
    Location
    Mount Dora, FL, USA
    Posts
    20

    Default Good afternoon gentlemem: I f

    Good afternoon gentlemem:
    I finaly made it to North Carolina to pick up my tools. I started on this motor this morning by removing the carbs for rebuild with carb kits. I now have most of the tools I will need including an air compressor. I am determined to make this engine purr like a kitty cat. Will keep everyone informed of my progress.

  17. #47
    eric eddington's Avatar
    eric eddington Guest

    Default what ratio to mix my oil in ga

    what ratio to mix my oil in gas on 1986 90 hp johnson motor

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