Johnson 70 Runs Great Then Will Not Start

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
stoekd3
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Johnson 70 Runs Great Then Will Not Start

Postby stoekd3 » Sun Dec 03, 2017 10:29 pm

Hey guys--I recently bought for my son and daughter--and of course for me too--- a 1983 15-footer with a Johnson 70-HP. She is pretty. However, the [Johnson 70-HP outboard engine] will run fine one day, then the next day it will not crank. Three days ago this happened:
    --[engine] started right up
    --let [engine] idle for about 10 mins
    --put [engine] in reverse and [engine] died
    --started again and in reverse died, then
    --I tried again and [engine] ran
    --actually ran great
    --bogged for a split second when I went full throttle but once on plane [engine] ran great
    --ran [boat] for about an hour with no [problems]
    --tried to take [boat] out today but when we put [boat] in the water [engine] would not start.

The battery is new, the plugs were replaced, and a water-separator filter was installed in late April. I have noticed that the primer valve does not click when I push in the key. But [engine] started and ran great two days ago.

I figure I have some sort of fuel [problem], perhaps clogged fuel lines. [The fuel hose is rated] B1. I will switch to A1 hose. Maybe [the gasoline fuel was] bad.

I am going to check the water-separator tomorrow as well put new [gasoline rated] REC-90.

Any other thoughts? Thanks

flymo
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Re: Johnson 70 Runs Great Then Will Not Start

Postby flymo » Mon Dec 04, 2017 5:29 am

No fuel problem will prevent the motor from cranking over on the starter - that has to be electrical. For starters, check the lanyard switch and jiggle the throttle to make sure it's really in neutral.

jimh
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Re: Johnson 70 Runs Great Then Will Not Start

Postby jimh » Mon Dec 04, 2017 7:44 am

You have to give more details about "will not start" and "will not crank."

Please choose from:
    --you turned the ignition key to START and nothing happened
    --you turned the ignition key to START and you heard the starter solenoid close, but the starter motor would not run or the starter motor could not rotate the flywheel at sufficient speed
    --you turned the ignition key to START and the starter motor turned over the engine at the usual cranking speed but the engine would not start and run.

jimh
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Re: Johnson 70 Runs Great Then Will Not Start

Postby jimh » Mon Dec 04, 2017 7:51 am

Is the fuel hose from the fuel tank to the engine made from a gray material with a metallic looking outer jacket?

stoekd3
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Re: Johnson 70 Runs Great Then Will Not Start

Postby stoekd3 » Mon Dec 04, 2017 11:50 am

flymo wrote:No fuel problem will prevent the motor from cranking over on the starter - that has to be electrical. For starters, check the lanyard switch and jiggle the throttle to make sure it's really in neutral.



Ok thanks I will check that now

stoekd3
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Re: Johnson 70 Runs Great Then Will Not Start

Postby stoekd3 » Mon Dec 04, 2017 11:51 am

jimh wrote:Is the fuel hose from the fuel tank to the engine made from a gray material with a metallic looking outer jacket?



It was :) I just ran out and bought A-1 black lines but it did have the b-1 gray lines on. I read another post where someone said these corrode easy and can restrict proper flow

stoekd3
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Re: Johnson 70 Runs Great Then Will Not Start

Postby stoekd3 » Mon Dec 04, 2017 11:54 am

jimh wrote:You have to give more details about "will not start" and "will not crank."


When I push in the key, I do not hear the primer valve click. The engine will turn over but will not start. It does this it seems every other boat trip. A couple days prior [the engine] started first try and ran all day perfectly.

I just bought new fuel hose. I am putting that on with some new REC-90, SeaFoam, and will try again.

I gladly and humbly take any thoughts

Thanks.

jimh
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Re: Johnson 70 Runs Great Then Will Not Start

Postby jimh » Mon Dec 04, 2017 1:18 pm

The fuel-enrichment method on some older OMC engines was to have an electrical solenoid operate a valve in the fuel system. The valve allows the flow of gasoline fuel into the intake manifold, bypassing the carburetors. This greatly enriches the fuel-air mixture for initial starting in cold weather. Usually there is a manual stem on that valve that also opens the flow of fuel into the manifold. If this valve is left partially open, you will get too much enrichment of the fuel-air mixture. To start the engine with such a rich fuel-air mixture becomes very difficult, and often impossible.

You should proceed as follows:

--locate the fuel enrichment valve and solenoid on the engine;
--look for a red handle on the valve that allows for it to be opened manually
--your engine operating guide should have details about the location of this valve; refer to them
--check that the manual valve is closed (clockwise to tighten).

If the valve is left partially open, you will have big problems starting the engine.

jimh
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Re: Johnson 70 Runs Great Then Will Not Start

Postby jimh » Mon Dec 04, 2017 1:21 pm

I also recommend you keep the can of SeaFoam sealed and unused. I don't know what sort of remedy you expect to get from a can of that very strong solvent, but I would keep it out of your fuel system, particularly now that you are going to replace all the suspect gray metallic B1 rated hoses with proper A1 rubber hoses.

Once you get the engine running and have fresh REC-90 gasoline fuel, you can begin to use an Evinrude fuel additive product to treat the fuel. Get Evinrude FUEL SYSTEM CLEANER and follow the recommended use. Also get some Evinrude 2+4C FUEL CONDITIONER for routine treatment.

You should also consider using a premium lubricating oil in the engine fuel, such as Evinrude XD50 oil. The best way to handle carbon deposit build up is to keep carbon deposits from forming by using best-quality fuel and oil.

You should also get a new primer bulb. I would get a fuel hose and primer bulb assembly from an OMC dealer. They make very good quality hose and primer bulbs, and getting it put together with Oetiker clamps will make for a cleaner installation.

Proper priming of the fuel system is very important to good starting. Review the operating guide. Note that the direction arrow on the primer bulb should be oriented with the arrow pointing upward to the sky for best operation.

A two-stroke-power-cycle classic outboard engine with carburetors that is in good tune, has proper fuel line priming, and is properly adjusted for starting should start in just a few rotations of the flywheel in almost any weather conditions. My old OMC V6 started without any hesitation for years and years, as long as I followed the recommended procedure. You really need to read the operating guide to find out the exact procedure. If you just ignore the recommendations and try willy-nilly to start it, you can spend a lot of time cranking without success. I am not kidding--read the manual and follow the exact procedure. In many cases there should be NO ADVANCEMENT of the throttle off the idle position during cranking.

jimh
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Re: Johnson 70 Runs Great Then Will Not Start

Postby jimh » Mon Dec 04, 2017 1:28 pm

If there is no actuation of the electrical solenoid for the fuel enrichment circuit, check the wiring between the ignition key switch and the solenoid. The typical wiring is shown in the REFERENCE section article at

http://continuouswave.com/whaler/refere ... witch.html

The circuit for the enrichment solenoid is usually carried on a conductor with insulation with VIOLET and WHITE stripes. If you are acquainted with basic DC circuit analysis, you should be able to see +12-Volts at the solenoid when you push in the ignition key.

stoekd3
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Re: Johnson 70 Runs Great Then Will Not Start

Postby stoekd3 » Mon Dec 04, 2017 6:43 pm

jimh wrote:If there is no actuation of the electrical solenoid for the fuel enrichment circuit, check the wiring between the ignition key switch and the solenoid. The typical wiring is shown in the REFERENCE section article at

http://continuouswave.com/whaler/refere ... witch.html

The circuit for the enrichment solenoid is usually carried on a conductor with insulation with VIOLET and WHITE stripes. If you are acquainted with basic DC circuit analysis, you should be able to see +12-Volts at the solenoid when you push in the ignition key.



Can not thank you enough for your input I REALLY appreciate it. Here is an UPDATE

I put new A1 fuel hoses, all new clamps, a new portable tank with REC-90 I filled today, and a new primer bulb-- all OEM. The engine started right up. I let it idle for about 15-minutes; no problems. I turned off the engine, waited about 20-minutes, and tried again: it started first try.

I took out the 15-gallon tank and will clean it tomorrow, I did find something weird inside: there was some sort of cap inside the 15-gallon tank; it looked like some sort of oil cap or something.

I checked the water separator and there was no water; there was small debris inside, but not a lot.

So I am stumped. Was [the problem] the gasoline, the lines, or potentially the debris? Or did it start as a fluke again? I am going to take her for a sea run tomorrow to see if it starts up again.

jimh
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Re: Johnson 70 Runs Great Then Will Not Start

Postby jimh » Tue Dec 05, 2017 12:18 am

I bet that old oil bottle cap was probably dropped into the fuel tank when someone was pre-mixing oil with the gasoline.

Thanks for the follow-up on the engine repairs and starting. The funny thing about an outboard engine: once the darn thing fails to start, you always are a little anxious about it ever starting again. I had a few weeks with my older Evinrude engine when some electrical gremlin was stopping the starter motor solenoid from operating. I checked everything I could think of, but nothing seemed to fix the problem. Finally I replaced the solenoid--even though it never appeared to be the problem--and I never had a no-crank situation again. But I used to always have a bit of anxiety if I was a long way from the dock and had to start that engine.

stoekd3
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Re: Johnson 70 Runs Great Then Will Not Start

Postby stoekd3 » Tue Dec 05, 2017 11:20 pm

Another quick update: it rained so I didn't take out [the boat] today but I did start [the Johnson 70-HP engine] in the driveway, again with the portable tank, new A1 lines, and REC-90 fuel. The engine started first try and idled for ten minutes with no problem. I will take it out Thursday to test it out and give an update.

Now I am thinking [the cause of the starting problem] was either the gray B1 fuel line had corroded and had a small blockage or the debris in the fuelwater separator. The gasoline fuel didn't look bad when we took it out of the old tank. Will learn more Thursday.

jimh
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Re: Johnson 70 Runs Great Then Will Not Start

Postby jimh » Wed Dec 06, 2017 7:11 am

What is typically seen in the gray B1 fuel hose is a separation of the inner liner material from the inner wall of the hose itself. Any suction in the fuel hose pulls the liner into constriction, impeding fuel flow. Generally you don't see this at engine starting. Usually at engine starting the primer bulb is operated and pushes fuel into the downstream hose, putting positive pressure into the fuel hose and expanding the liner back against the walls of the hose. But after the engine starts and runs, the fuel lift pump puts suction on the hose as it tries to lift fuel from the fuel tank, and then the walls collapse. I would expect that deterioration of the gray B1 fuel hose would cause a problem after the engine starts, when the engine is run at higher throttle settings, and the engine fuel lift pump tries to pull more fuel up from the tank.

stoekd3
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Re: Johnson 70 Runs Great Then Will Not Start

Postby stoekd3 » Fri Jun 22, 2018 9:23 pm

Update: It turns out it was the power pack, put a new one on and has been running pretty good.