1997 johnson 115 motor issues

Mako_OneMako_One Posts: 216 Officer
My boat sat for a while, but I used startron and started it when ever I could. I used the fuel in power washer with out any issues. I finished up my console and rewire and start it up on the hose. She ran great! I take her out an fill up the tank (97 Mako 171) which took about 11 gallons which means there was about 20-25 in the tank. I take her for a run on the Indian River and she runs great. Second trip out I have a little hicupp, kind of like fuel starvation. It runs fine the rest of the outing. On my third trip out I put in another 15 gallons and it runs good, then begins to surge like if it ran out of fuel, then takes off. it does this for a few minutes and then can't get it over 4K and alot of vibration. I'm thinking fuel issue somewhere, I had already replaced the racor type filter so I decided to run it off a seperate fuel tank. I take her out and same issue runs ok then bogs down then surges.

So since I just couldn't figure it out I take her to a local mechanic. He calls me up an says top right cylinder is 20 lbs lower than the rest. 130 on the others. I describe to him the issue i had and he says the lower compression should not have affected it. I tell him put it back together and figure out what the original reason for bringing it in. calls me up a few days later and tells me the vapor seprator cover was warped and needed to be replaced. I give him the go ahead and I pick it up and take it out. SAME OLD SHYTE!!

The mech says it needs to be rebuilt at a cost of around $4k :cry

Any ideas on this issue?

Replies

  • screamin seamanscreamin seaman Posts: 1,492 Officer
    First, if there is any fuel restriction on a two stroke engine it will eventually cause some serious internal damage (may be why one cylinder is low) from running lean.

    Vapor seperator?? This is a carbureted engine, correct? If so they don't have vapor seperators!

    Sounds like a carb/carbs are running out of fuel. When the power drop occurs did you go back and squeez the primer bulb? If you do this it will probably gain back the RPM's because it's getting the fuel it needs. Then it's time to find out why it's not getting fuel.

    If you prime the bulb with the cowling off do you see fuel squirting out of any fuel lines?

    I wouldn't worry about the -20 cylinder right now. But get a compression tester and keep an eye on that cylinder.
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  • Mako_OneMako_One Posts: 216 Officer
    Yeah it does have a vapor seperator and it is carbed.

    I thought the primer bulb was the issue, but while it was running I squeezed the bulb and nothing happened- no difference in performance and it wasn't sucked closed.
  • screamin seamanscreamin seaman Posts: 1,492 Officer
    So your saying that when it dropped RPm you went and squeezed the bulb and it did not gain back the R's?
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  • aboveboredabovebored Posts: 1,227 Officer
    sounds like you might have a bad ignition coil. Runs good, heats up, fails. Also, you may want to find another mechanic.
  • screamin seamanscreamin seaman Posts: 1,492 Officer
    Definitely could be spark related. Put a timing light on each plug wire once it starts it's temper tantrum.
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  • Mako_OneMako_One Posts: 216 Officer
    currently it starts the hesitation just after pushing off the dock. I can throttle up just a little with no issue, once I am past 1500-2000 it acts up.
  • screamin seamanscreamin seaman Posts: 1,492 Officer
    Take it to a mechanic... a better mechanic than the last one.
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  • BillgranBillgran Posts: 334 Deckhand
    You need a trained tech to find out first if it is a fuel problem or an ignition problem, then troubleshoot the system to find the root cause of your problem.
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    "There is never just one thing wrong with a boat"
    --- Travis McGee


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  • Pat LPat L Posts: 440 Officer
    20lbs lower compression, I would think something is going bad internally. I would atleast pull the head off.
  • Mako_OneMako_One Posts: 216 Officer
    I'm looking at repowering with a new etec. I think the vibration might be internal and it won't let the motor power up into the higher rpm range. I'll pull it off the boat and place it on a stand and make it a project. I'll rebuild it and maybe find another hull to hang it on. Thanks for the suggestions.
  • screamin seamanscreamin seaman Posts: 1,492 Officer
    For the record, I love my Etec!
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