Johnson V4 90 HP idling problems

[waselius]

I am starting the engine and warming it with the fast idle lever. When i close the lever for normal idle speed the engine runs for a while but suddenly stops. After that it is very difficult to start the engine.
I have cleaned the complete fuel system and there don?t seem to be any leaks. New spark plugs. Could it be something with the ignition or is my fuel pump "on the blink".
When I actually drive the boat at speed the revs varies.

 

[tashasdaddy]

Re: Johnson V4 90 HP idling problems

carb contaminated, float level out of adjustment, link n sinc not correct.

 

[waselius]

Re: Johnson V4 90 HP idling problems

I am sorry, but I don't really know what link n sink is. As I have not tinkered with outboards before and I live in Sweden "link n sinc" is an expression I have never heard about.

 

[emdsapmgr]

Re: Johnson V4 90 HP idling problems

Tas is referring to the service manual procedure to match the carb throttle position with that of the spark advance. It's a good basic tuning procedure outlined in the factory manual. The idle could be set too low. Make sure the idle timing is set ok. The engine idle should be set when the engine is floating in the water. 650-700 rpm when in gear. If the engine rpm's vary when at speed, you could have a weak fuel pump. Try constanly priming the fuel hose bulb when this happens and see if the engine smooths out.

 

[waselius]

Re: Johnson V4 90 HP idling problems

As I am swedish (my english is pretty good, married to an english woman) there are still expressions and explanations that are difficult to grasp.
I have adjusted the float level, the carburettor is cleanedand I have changed the fuel pump to one from my 55 hp that worked when I removed it but the symptoms are exactly the same. First it idles OK, but suddenly it starts to feel like misfiring and eventually stops. After that it is impossible to start it.
I have not yet done a link-n sync as I don't really understand it. I have the service manual. Can you tell me the page it is described. I really appreciate this forum. Thank you!!

 

[ezeke]

Re: Johnson V4 90 HP idling problems

Should be in the first section of the factory service manual under "Synchronization and Linkage Adjustments".

 

[waselius]

Re: Johnson V4 90 HP idling problems

Thank you lots!!

 

[waselius]

Re: Johnson V4 90 HP idling problems

Eventually, my daughter (who bought the engine) got fed up with my effort to try to get the engine to work properly and had it sent to an expert on a local firm. The verdict was the engine is a complete right off and should be sold as spares. The engine had a noise that would make it seize after a couple of hours. I actually do not believe that. I have built cars and car engines since I was 18 years old so boat engines cannot be that different.

Sorry about the blabbering but here is the question this time. The say that the "power pack" is completely gone. Can the engine function if the power pack is faulty. The boat actually worked fine at speed initially, it was actually the idle that was not ok. So, what does the power pack do?

 

[mamm7215]

Re: Johnson V4 90 HP idling problems

power packs control the voltage and current to the coils and power to the other systems, I believe. Get a manual, that'll help. They are not expensive (relatively) and easy to replace. If it is only a power pack, the motor is certainly not shot. If they meant power head, however, that's bad news.

 

[waselius]

Re: Johnson V4 90 HP idling problems

"Here we go again"
I have checked the ignition. Spark test was fine. Good sparks at spark plugs. Timed the engine using Joe Reeves method. Compression 110 on three, 100 on one cylinder with cold engine. Gone through he carburettors again. All orifices are clean. Done the float levels. The only thing that I have not done is open up the small lead core plugs. I don?t even know what they conceal. I got a rebuild kit for the fuel pump. So after all this effort I thought, now it must work.
No, way!! It started after some effort whith the help of starting gas. Started, sounding good. Worked well for about a minute, started to go bad and stopped. After that it was impossible to get it going. The engine did not even cough. I checked the spark plugs and they were all wet like the cylinders had been flooded. I have now reached the point when I have no more answers.
Maybe some of you have some ideas what i could be.

 

[mamm7215]

Re: Johnson V4 90 HP idling problems

Compression, spark, fuel. You have compression. Carbs cleaned so flow should be good (I assume??). Have you tried to pump fuel ball in line while initially idling to see. Perhaps there's a restriction in your lines/tank. Replace fuel lines if they are old. Also, try starting without the front cover over the carbs and see if there's a mist blowback out of the carbs. That would indicate bad reeds. That leaves spark. Good spark at initial testing is one thing. Bad stator or timing ring below flywheel can start motor but fail as it warms up if components are bad. Replace fuel lines, even try another tank to eliminate physical fuel line problems. Try to find out why the 'experts' say motor is shot.

 

[Rscardina]

Re: Johnson V4 90 HP idling problems

have you checked the choke solenoid? it may be leaking by causing the engine to flood on you.

the choke solenid is the small black unit that has a red lever on it. usually near the vro pump.

make sure it is in the correct position and remove one of the lines that exits the solenoid, add a small piece of hose goint to a bucket to see if you get gas from it.... when you try to start...

keep in mind, you will get gas when you push the key in to choke the engine...but after it starts,...you should not get gas from that hose. if you do then your solenoid is leaking by flooding you out

 

[waselius]

Re: Johnson V4 90 HP idling problems

I checked the choke solenoid and found it ok in every aspect. I cleaned and dried the spark plugs and tried again. I pumped up the fuel pressure but it did not start with petrol. I sprayed start gas and it started but stopped after a couple of seconds. Now I realized that the petrol level sank in the fuel filter. I pumped it full again and the level sank again. Where did the petrol go? Was the pump faulty so the petrol went back in the tank? I positioned the tank above the engine but the same thing happened again. Then i realized that about one liter of fuel had disappeared. Where had the fuel gone? The engine had not started on petrol at all.
What the can be wrong with this bloody engine?

 

[mamm7215]

Re: Johnson V4 90 HP idling problems

sounds like your bulb is shot, have you replaced it? And your fuel lines?

 

[waselius]

Re: Johnson V4 90 HP idling problems

the bulb is brand new.

 

[Rscardina]

Re: Johnson V4 90 HP idling problems

sounds like an air leak in the gas line somewhere.... the fuel should not run back..unless the syphon valave at the tank is bad, or there is a leak between the tank and bulb or the bulb is bad...

i'd start with looking at all that first,,,if the fuel level goes down then its flowing back to the tank..the fact that you have air in the seperator tell me your leak is either at the seperatpr or somewhere between the engine and seperator...

if your fuel pump was bad or leaking it could let air in when off but your primer bulb should not let it go back down since it has a one way check valve in it...

 

[cougar1985]

Re: Johnson V4 90 HP idling problems

make sure your fuel connections are ok and functioning properly.pay particular attention to the connection from the the end of the fuel tank hose to the one on the motor where they mate.many times ive seem them loose for what ever reason and it can give you your symptons exactly.make sure you have a positive click when you attach.happened to me many years ago ,my motor wouldnt keep running and it was driving me nuts,went to the connection and pushed it and click!after, a perfect running motor.why did it do that? i dont know, but i always check that first now.just a thought.

 

[mamm7215]

Re: Johnson V4 90 HP idling problems

I know this sounds sill to ask, but is your bulb installed in the right direction?

 

[waselius]

Re: Johnson V4 90 HP idling problems

I actually had enough with this bloody engine so I decided on drastic unconventional action.
When I realized that I could not keep the fuel pressure and the fuel seem to disappeared without the motor working I decided to take away the fuel pump altogether. First of all I wanted to know if the carburetors were leaking. I bolted them together with a flat alu rod, took them off and stuck them over a bucket. I did not want leaking fuel on the floor. I attached the fuel hose with the bulb directly to the carburetors. The bulb became firm and stayed firm. No leaks whatsoever. After attaching the carburetors, I got an electric fuel pump and swapped it with the bulb. The engine started and kept going. As I did not have the engine on the boat I could not get it up to proper temperature. After stopping and starting a couple of times I actually think my problem is solved. OK, traditionalists probably say that you should use the vacuum pump, but I want my engine to work. Up here in Sweden the season is short.
Anyway, thanks for all the inputs.

 

[waselius]

Re: Johnson V4 90 HP idling problems

i thought that all I done in this matter would have resulted in a engine that worked properly. But I was mistaken.
I have installed a brand new OMC power pack and new Champion spark plugs. The only things I have not done is open up the core plug. I do not know what is behind it. I have not done anything to the recirculation system either.
It starts absolutely perfect when cold. Reversing or going forward works smoothly, and at speed it is really good. I was out on the lake about ten, fifteen minutes and went back to were I moor the boat. I wanted to try to trim up the engine because there are lots of shallow areas in the lake. The engine stopped, and after that I could not get it started. After a lot of tries it started only when I used the starter solenoid. Eventually I got it working on idle, but as soon as I moved the lever forward it stopped. It was impossible to move the boat. The day after I decided to take the boat up an tow to my workshop. The engine started without any problems and it behaved perfectly when I drove the boat to the ramp. What is the problem with this as I feel a wonderful engine when it works. I have a feeling it must be a fuel problem?
I am somebody that cannot give up. This problem has to be solved. There seem to be so much more knowledge where you are than in Sweden.