July 6, 2019 at 8:41 pm #178509
I have a 1967 Johnson 3hp motor that was running like a top two years ago. I left fuel in it, and now (yes… I know… ) it will not run properly.
I’ve cleaned the carburetor, changed all the gaskets with the exception of the gasket between the carb and block. I changed the lower gearcase oil, put in a new orifice, changed the plugs, rinsed the fuel tank, changed the fuel hose, and added fresh fuel. It starts on the first pull every time, but it will not go to high speed when the magneto lever is moved all the way to the right. It will go to high speed, in spurts, but not maintain the high rpm. All I can think of that could be left is to change the condenser & points and check the timing. However, the timing should be fine, as the carb and linkage were never moved from when it was running great. Those bolts were not loosened.
I’m running out of patience (and knowledge) to fix this. Is there someone in the area that can help me? All the local marinas turn me away because the motor is too old. Even the marina on 110 in Amesbury, where I had found help two years ago won’t look at it. The “old man” who did the antique engine work there has retired. Nipmuc Auto & Marine, where I brought it when I resurrected it 15 years ago, has closed permanently.
Can you point me in the direction of someone who can help me? I am located in Plaistow, NH.
This is only minutes from one of your upcoming events – the Lowell Antique Outboard Meet on September 15th. I’d love to get my motor running and bring it down to show it off. It belonged to my great uncle, and it’s been in my family since I was a child, so it has great sentimental value to get it running again. It really is a beauty!
US Member - 2 Years
Topics: 32July 7, 2019 at 8:13 am #178523
I am in Providence, not that close. Yes, most dealers aren’t going to mess with your engine, and that is probably for the best. Today’s techs have little/no experience with your engine, so you would be paying big bucks for less than experienced service. I have a dealer that would help, but he is even farther away from you in Ashaway RI.
You mentioned replacing the “orifice”, does that mean you replaced the high speed fixed jet (brass jet that threads into the carb bowl/ not the drain plug)? It is difficult to replace this orifice without the proper OMC jet screwdriver.
Did you have the carb bowl off? If so, was the carb dirty/fouled inside? Was the cork nozzle gasket still in place? You mentioned rinsing the fuel tank out, was it dirty/fouled inside? This engine has a fine filter incorporated into the shut off valve which gets plugged up fairly easily, did you have the air vent open? Try removing the fuel cap and running the engine.
I’m guessing your surging issue is fuel related, but an ignition issue is surely possible as well, did you try different plugs? I would have to hear the engine run /misbehave in order to pinpoint the problem system. Has the ignition been serviced lately?
In any event, the fuel and ignition systems should be serviced in order to make this engine “a reliable daily runner”. The water pump impeller should be replaced also. Sounds like this is a beautiful engine that has nice memories for you, so it surely deserves the best care so it will run for another 50 years.
Feel free to post a video of the engine misbehaving so we can help point you in the right direction. Feel free to contact me personally also….Don
US Member - 1 Year
Topics: 128July 7, 2019 at 8:16 am #178524
By the time I posted a reply Fleetwin had
already responded. His response covered
everything I had to offer an much more.
So I would like to just deled my attempt
to reply but I cant. Once you hit submit
you most post something so – I’m posting
US Member - 1 Year
Topics: 43July 7, 2019 at 9:24 am #178531
You said “. It will go to high speed, in spurts, but not maintain the high rpm” That tells me that it is running on one cylinder with the second cylinder cutting in and out. If new plugs didn’t fix it, time to pull the flywheel and fix the ignition. Probably has cracked coils.
US Member - 1 Year
Topics: 6July 7, 2019 at 9:56 am #178532
I agree with Frank. Time to check ignition components under the flywheel.
I am in Bethel, Maine and would be glad to help if that works for you.July 8, 2019 at 4:08 pm #178620
Dear Fleetwin, Tubbs, Frankr, and David,
I appreciate all your responses! Thank you!
To answer all of you simultaneously:
I have replaced the high speed jet (I have the proper jet screwdriver tool).
The carb was NOT dirty or fouled, and there was little to no evidence of lacquer. I rinsed it out with carb spray cleaner. When I rebuilt this engine back in 2012, it was completely fouled with lacquer.
I’ve seen what that looks like, and this carb should be clean. The fuel that was left in it was NOT ETOH fuel. It was a mix made with non-ethanol small engine fuel.
The fuel tank was rinsed with fresh fuel. The fuel filter is not fouled – fuel runs smoothly through it, at a speed fast enough that the fuel bowl SHOULD stay filled, but perhaps that is still the problem. I doubt the engine could consume fuel that fast… The air vent was open – in fact, it was removed, as it often vibrates free. I just take it off when I’m running.
The plugs are brand new, are the proper plug, and they were properly gapped.
The ignition has NOT been serviced. The shed in which it was stored had an issue with tools rusting due to condensation. As a result, I had started to wonder if the points are rusty, or the condenser was failing. The last time I rebuilt it, I borrowed a flywheel puller and changed them. I just purchased a flywheel puller and had planned on checking the points. That was next on my list, as they’re relatively inexpensive to replace. Your suggestions give me even more reason to pull the flywheel. I will also check the coils for damage.
The water pump impeller was replaced in 2012, and water still moves through the engine properly – a fine mist can be felt coming out of the exhaust ports – I can feel that when it’s running at lower speeds.
I was also contacted by JPMoffat who is running your AOMCI Lowell Antique Outboard Meet this September. He lives minutes from me in Salem, NH and thinks he can help me.
I will get to the motor later this week and see what’s “under the cover” when I pull the flywheel. I will post results!
US Member - 2 Years
Topics: 32July 9, 2019 at 10:47 am #178656
Do a spark check before pulling the flywheel to confirm your suspicions….Try running the engine with those inline neon testers to help pinpoint an ignition problem also. You could have any number of issues under that flywheel, the more you do to pinpoint the issue, the quicker it can be resolved….
Jim is a great guy, please say hello from me…DonJuly 9, 2019 at 10:55 am #178660
I spoke with Jim last night. He gave me the same advice. I will have to shelve the project for a bit, but will pick it up in early August. I hope to have the motor running for Lowell meet in September!
I will pass along your greetings when we speak again!
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