Blocking Diodes, will this solve my slow mode situation

[maui al]

Several months ago my 130 hp Johnson 1996 goes in slow mode while retuning to port in very rough seas and heavy winds. No alarms or led lights came on. Continued running the engine in slow mode and after a few minutes it would go back to higher revs. Did this about three or four times over a course of 6 miles, I even used the kicker to try to maintain forward speed and control while heading into this heavy wind blown chop and 20-30 mph winds. We made it back to port and it took 2.5 hours on what normally takes me 40 minutes to come in even if the sea and wind conditions are rough for the last 6-7 miles. The engine would not start at wash down time. I decided that to take it in to the local dealer. The think the found the problem and replaced the power pack and the port temperature sensor, the one with the two leads.

At first the repair shop said that it was only the power pack, I okayed that repair and when they finally got the part and installed it they said that I needed another part which was the temperature sensor, the one with two leads.

Picked up the boat and took it out for a day of fishing, the engine did not go into slow but was idling very rough so took it back the next morning for an adjustment which was a quick in and out visit.

The motor went into slow mode again once only on another fishing trip a month or two later, but it came out of slow mode so I did not take it back in to get checked.

This past week, First week in March 2011, once again on the return trip to port from 14 miles up we encounter a smaller chop and winds only up to 20mph, but the engine goes into slow mode. I run with it this way and then it dies and I have to use the kicker to get back under way. After 10 to 15 minutes the engine starts can go back to high revs. We continue to the harbor with the main engine and the kicker going. Once again no alarms or warning lights.

Took the boat out again the next day to try and get in on the last couple of days that bottom fishing season is open. 4.5 miles out and traveling at 4500 rpm the engine goes into slow mode again. The next day the Japanese Tsunami hits. After a few minutes the engine works again and we turn aroung and end our fishing trip. Since it?s the end of bottom fishing I will not use the boat again until September 1, 2011, and I have the time to look for the problem myself.

These are the steps that I took looking for my problem. I tested the old temperature sensor that the dealer took out and it worked. Put it in a pot of water and connected a test meter. When the water got hot enough it worked. So one of the questions that came up was why did the dealer need to change this in order to solve my engine problem four months ago? I proceeded to take out the two temperature sensors in the motor and test them, they worked. I took apart the thermostats and tested them and they also worked, also looking into the housings there were clear passages and no build up of salt or hard water scale.

I replaced the impeller on the water pump last year and the pee stream is strong and when the engine is running the temperature was cool enough to have it run over my hand.

I next tested the brown leads on the temperature sensors and shorted them to ground and they lit up the warning light on the instrument panel, but no alarm or horn sounded. When you turn on the key the warning horn goes off and the leds come on and then goes off in sequence.

I removed the oil tank and dis-connected the four prong connector and found that connector in the bottom of the cowling covered with an oil slick and green stuff on the prongs. The brown lead when you short it out would light the oil led. I did not know that this connector was sometimes underwater (salt water that gets into this area). So I need to waterproof the end of this connector and keep it tied off the bottom of the cowling. Today I also notice another two wire item that has open ends sitting at the bottom of the cowling. I will remove the cowling and see where that goes.

I read in your treads about the blocking diodes and finally after looking up the part from one of the online parts supplier I found out that they are located in the wiring harness. The manual has a test procedure for these diodes and I preformed the test and found one was defective. Ordered one from a dealer on Oahu and should get it in a couple of days, and then I will install it.

Questions I need help with.

When the temp lights go off should the alarm also go off?

Can a power pack be tested to find out if it is defective or not. I have the one that the dealer took off that I believe works and that he replaced the one on the engine because that was probably a good guess to solve the trouble, but then after they install it they say that I need a temp switch in order to get it running, makes me question their skill or are they just replacing parts until they get it right.

Any opinions if I have any recourse against the dealer?

Any other suggustion on what my problem might be?

 

[maui al]

Re: Blocking Diodes, will this solve my slow mode situation

Additional information. The two wire lead went to the oil tank, a B and a T/B. The ends were cut before the connector and the end wires showed signs of sitting in water and corrosion. The four prong plug went to the vro pump, Pr,Gr,B,T/Y, this plug also was sitting in water and the male connectors were corroded with green stuff on them. My fix for these will be to seal up the wires so they cannot be shorted and maybe solve some of my problems.

 

[boobie]

Re: Blocking Diodes, will this solve my slow mode situation

Your mtr should only have one blocking diode because it doesn't have a shift switch. If the diode is bad, yes it can throw it into Slow for no apparent reason. When the temp lite goes on you should get a horn for 10 seconds. The only way to test the power pack is to try it on the mtr.

 

[SparkieBoat]

Re: Blocking Diodes, will this solve my slow mode situation

did you try disconnecting the temp sensor wire from the sensor to the power pack? I hope you kept your old power pack ..it was probably good.

 

[daselbee]

Re: Blocking Diodes, will this solve my slow mode situation

The horn will only sound if the engine is running. If key on, not running, the lights will work, but no horn. This is absolutely spelled out in the OMC service manual at the bottom of page 7-32.

 

[boobie]

Re: Blocking Diodes, will this solve my slow mode situation

Sorry, I was assumeing the mtr would be running when the lite went on.

 

[daselbee]

Re: Blocking Diodes, will this solve my slow mode situation

This one really got me the first time. Normally you would just ground the appropriate tan wire, and test the horn. That was what I was doing. Key on, tach lights cycle, then I grounded the stbd temp sensor. No horn. Well two days later, harnesses swapped, the whole nine yards, I was finally informed by jwbmarine over on marineengine.com that the horn will not sound unless the engine is running.

Duh....you guys...learn from others experiences...OK?

 

[jonesg]

Re: Blocking Diodes, will this solve my slow mode situation

Several months ago my 130 hp Johnson 1996 goes in slow mode while retuning to port in very rough seas and heavy winds. No alarms or led lights came on. Continued running the engine in slow mode and after a few minutes it would go back to higher revs. Did this about three or four times over a course of 6 miles, I even used the kicker to try to maintain forward speed and control while heading into this heavy wind blown chop and 20-30 mph winds. We made it back to port and it took 2.5 hours on what normally takes me 40 minutes to come in even if the sea and wind conditions are rough for the last 6-7 miles. The engine would not start at wash down time. I decided that to take it in to the local dealer. The think the found the problem and replaced the power pack and the port temperature sensor, the one with the two leads.

At first the repair shop said that it was only the power pack, I okayed that repair and when they finally got the part and installed it they said that I needed another part which was the temperature sensor, the one with two leads.

Picked up the boat and took it out for a day of fishing, the engine did not go into slow but was idling very rough so took it back the next morning for an adjustment which was a quick in and out visit.

The motor went into slow mode again once only on another fishing trip a month or two later, but it came out of slow mode so I did not take it back in to get checked.

This past week, First week in March 2011, once again on the return trip to port from 14 miles up we encounter a smaller chop and winds only up to 20mph, but the engine goes into slow mode. I run with it this way and then it dies and I have to use the kicker to get back under way. After 10 to 15 minutes the engine starts can go back to high revs. We continue to the harbor with the main engine and the kicker going. Once again no alarms or warning lights.

Took the boat out again the next day to try and get in on the last couple of days that bottom fishing season is open. 4.5 miles out and traveling at 4500 rpm the engine goes into slow mode again. The next day the Japanese Tsunami hits. After a few minutes the engine works again and we turn aroung and end our fishing trip. Since it?s the end of bottom fishing I will not use the boat again until September 1, 2011, and I have the time to look for the problem myself.

These are the steps that I took looking for my problem. I tested the old temperature sensor that the dealer took out and it worked. Put it in a pot of water and connected a test meter. When the water got hot enough it worked. So one of the questions that came up was why did the dealer need to change this in order to solve my engine problem four months ago? I proceeded to take out the two temperature sensors in the motor and test them, they worked. I took apart the thermostats and tested them and they also worked, also looking into the housings there were clear passages and no build up of salt or hard water scale.

I replaced the impeller on the water pump last year and the pee stream is strong and when the engine is running the temperature was cool enough to have it run over my hand.

I next tested the brown leads on the temperature sensors and shorted them to ground and they lit up the warning light on the instrument panel, but no alarm or horn sounded. When you turn on the key the warning horn goes off and the leds come on and then goes off in sequence.

I removed the oil tank and dis-connected the four prong connector and found that connector in the bottom of the cowling covered with an oil slick and green stuff on the prongs. The brown lead when you short it out would light the oil led. I did not know that this connector was sometimes underwater (salt water that gets into this area). So I need to waterproof the end of this connector and keep it tied off the bottom of the cowling. Today I also notice another two wire item that has open ends sitting at the bottom of the cowling. I will remove the cowling and see where that goes.

I read in your treads about the blocking diodes and finally after looking up the part from one of the online parts supplier I found out that they are located in the wiring harness. The manual has a test procedure for these diodes and I preformed the test and found one was defective. Ordered one from a dealer on Oahu and should get it in a couple of days, and then I will install it.

Questions I need help with.

When the temp lights go off should the alarm also go off?

Can a power pack be tested to find out if it is defective or not. I have the one that the dealer took off that I believe works and that he replaced the one on the engine because that was probably a good guess to solve the trouble, but then after they install it they say that I need a temp switch in order to get it running, makes me question their skill or are they just replacing parts until they get it right.

Any opinions if I have any recourse against the dealer?

Any other suggustion on what my problem might be?

It will not come of SLOW unless you reset the ignition by turning the key off, so it doesn't sound like SLOW.
The common denominator sounds like rough choppy weather stirring crap up in the tank and clogging the carbs.

 

[SparkieBoat]

Re: Blocking Diodes, will this solve my slow mode situation

well I have 4 OMC motors from 1989-1995 and the over heat alarm will sound if i ground the tan wire with key on and engine not running, on my engines anyway. The tan wire does not go through the power pack, it feeds directly to the horn, and my horn is powered by key switch, so if key is on and tan wire gets grounded horn buzzes. Maybe the harness change in 1996 did something different..Jones brings up a good point about the SLOW mode..unless something is wrong with the power pack SLOW mode will stay on until you shut engine off and restart.

 

[daselbee]

Re: Blocking Diodes, will this solve my slow mode situation

Yes, absolutely, Sparkie. 1996 changed to the Systems Check monitoring system. Deutsch connectors. Engine must be running on 1996 and up Systems Check models for the horn to sound.

If you have the "big red plug" then the warnings work like Sparkie's example.

Edit: One other thing. The horn on Systems Check engines is driven by the tach (or the optional Horn driver module if you have no tach). The circuits for sounding the horn are all tach controlled. A tan wire with a blue stripe drives the horn.

 

[maui al]

Re: Blocking Diodes, will this solve my slow mode situation

Thank you for all the replys. There is a lot of knowledge in the membership. Mahalo for all the advice.
1. The dealer did return the old power pack to me.
2. The dealer alos returned the temp sensor to me. so I now have some good spare parts.
3. I will try the horn alarm the next time I have the engine running to see if the alarm will sound and the lite will lit. So far my test were only with the ignition switch turned on.
4. Fuel supply maybe a problem. The boat has a 70 gallon fuel tank and built in 1996 and probably has not bee drained or cleaned out since then. Usually when I go out the tank is full or at least nearly full. On the last two trips the tank only has about 45 gallons to start.
I think the tank has at least 30 gallons still in it. Gas in Maui is currently $4.25 a gallon for the regular grade. In the past six months during the open bottom fish season I went out 45 days and purchased at least 900 gallons of gas. I was trying to get the tanl low at the end of the season so there would be less gas to siphon out of the tank, pass it thru my raycor filter with the glass bowl on the bottom to see what comes out. The only access to the tank is the filler, Air vent hose, fuel line feed. The fuel gauage area is screwed to the tanl and covered with some kind of red color hardened type lookinf epoxy. I would open this up for inspection but that might be later.

Last year I has fuel supply problems with this engine. At high rpm 4500-5000 rpm the engine would start to studder. I finally had my crew start pumping on the primer bulb anf the engine would come back to high revs. Prior to that I looked over and replaced the entire fuel supply lines looking for air leaks or poor connections. I replaced the vro fuel pump with a pre-mix fuel pump and have not had fuel issues until now. As a rersult I have two sets of loose wiring floating around in the bottom cowling cover which will be addressed and corrected.
Any different ideas to get the gas out of my tank. By the way a six gallon portable tank I can travel 9 miles at 4500 rpm.
5. I took the electrical tape off the wirind harnes, but have not located the diode or diodes yet. I did not cut any wires yet. Waiting for the mail person to bring me the parts. If the timing is right we can get over night mail service between the islands.
6. The two not used wires, 4 wire vro pump and 2 wire to oil tank, will be cut off as close to the wiring harness connectors and the capped off with some kind of waterproof cap. The motor is on pre-mix, I am from old school and feel this is safer and have fewer parts to go wrong.
7. the odd part about the slow mode operation was that it happened on three different day, two was very windy and very choppy and the third day was completely flat and light winds. the other odd part was that the motoer would go into slow mode and a few minutes later it would allow you to go back to higher speed. I think the motor did this about five times, one of them was on the calm day. On the first rough day the motor never died, but the kicker was set up to try to give us more horsepower to get through the heavy winds and seas at some point the motor kicked in and allowed me to go back to higher revs. On the second rough day the motor died or shut off and after setting up the kicker and 10-15 minutes later the motor started and allowed me to go above 2500 rpm.
8, I have until September 1, 2011 to get my boat reliable for the opening for the bottom fish season.

 

[jonesg]

Re: Blocking Diodes, will this solve my slow mode situation

Its starting to sound like the fuel pump.

If it falters but picks up again IF someone pumps the fuel bulb? that definately points to the pump.
The fuel delivery (solid beeeeep) alarm at WOT does not require the ignition be turned off to reset...just throttle down and it stops.
If the pump is good and all hoses are clamped properly I would consider the vacuum checkvalve that powers the pump.

It sounds like fuel starvation, not slow.
A timing light would show whether its going into slow or not. One bank of cyl's shuts down and the engine shakes.

 

[SparkieBoat]

Re: Blocking Diodes, will this solve my slow mode situation

fuel pumps are a common failure on these motors. also check all fuel line connections, I have seen a worn out connector cause the same symptoms, first thing I do is test with a NEW fuel line and connectors.

 

[maui al]

Re: Blocking Diodes, will this solve my slow mode situation

Blocking diodes was not the problem... When I tested the diode connections I did not follow the instruction properly. The existing diode works. There are three brown wires coming into the diode and one going out. I made the assumption that tyhree wires were coming out og the diode, I guess I can not read wiring diagrams either because it does show that. The instructions from the diode installation package shows that.

I blocked off the two wire connector and the four wire connector that used to go to the vro pump. I will also pull up these ends to keep them out of the bottom of the cowling.

The next thing is for me to inspect all the fuel connections and lines, the fuel filter or change it, drain the fuel tank anf remove any rubbish and any thing else that might be suggested.

I plan to take it out for about a six mile run in flat water and hope the problem shows up again. This time armed with some new knowledge Imight get more insight on what the problem might be.

Thanks for yor replys.

 

[maui al]

Re: Blocking Diodes, will this solve my slow mode situation

I test started the motor to see if I put everything back together right. While it we running I grounded out the temperture wire going to the power pack and the light went and the horn sounded. There was no mistake about the alarm and that function does work. Thats the first time I have ever heard that engine do that.

The sea trial has benn delayed a day so it is shifted to Thursday.

 

[jonesg]

Re: Blocking Diodes, will this solve my slow mode situation

Thats an important alarm to have, you've probably had no overheat protection all this time.

 

[maui al]

Re: Blocking Diodes, will this solve my slow mode situation

Took the boat out today and problem solved, horray, horray,horray.

to make a long story short there was a leak on the 1/4 fuel line going to some kind of addiative imput spot that has a red turn handle. At the three way fitting The 1/4 hose was clamped on with a zip tie. That connection was leaking fuel at high rpms when the fuel pressure increased.

When the engine first slowed down we switched fuel tanks and nothing happened, then we started to pump on the fuel bulb ,but we could not get it to get solid. We swithced fuel hoses and tried it with another hose and still nothing, Took a brand new spare out and tried to pump with that and no change. We finally took the cover off and then started to start the engine, by the way all this time the engine woul not start and when we got it going it would die. DFinally my crew see's the spot where the fuel is leaking and the more we pump the more it leaked. We cut the small hose and put a new zip tie and that seemed to solve the problem.

The engine starts up easy, goes well in high speed as well as the lower rpm's.

Problem solved ...... Thank you everyone for your help. I would have never thought I had a fuel issue until several of you brought it up.

 

[jonesg]

Re: Blocking Diodes, will this solve my slow mode situation

Took the boat out today and problem solved, horray, horray,horray.

to make a long story short there was a leak on the 1/4 fuel line going to some kind of addiative imput spot that has a red turn handle. At the three way fitting The 1/4 hose was clamped on with a zip tie. That connection was leaking fuel at high rpms when the fuel pressure increased.

When the engine first slowed down we switched fuel tanks and nothing happened, then we started to pump on the fuel bulb ,but we could not get it to get solid. We swithced fuel hoses and tried it with another hose and still nothing, Took a brand new spare out and tried to pump with that and no change. We finally took the cover off and then started to start the engine, by the way all this time the engine woul not start and when we got it going it would die. DFinally my crew see's the spot where the fuel is leaking and the more we pump the more it leaked. We cut the small hose and put a new zip tie and that seemed to solve the problem.

The engine starts up easy, goes well in high speed as well as the lower rpm's.

Problem solved ...... Thank you everyone for your help. I would have never thought I had a fuel issue until several of you brought it up.

All it takes is a pinhole air leak, they sell newer nylon fuel line clamps that are better than the tie wrap style.
http://www.iboats.com/Snapper-Clamps/dm/*******.865733355--**********.661629238--view_id.271391

He shows you on this video what can occur with the zip ties.
http://www.youtube.com/user/TheMarineDoctor#p/u/10/SEbW-6eOc5I

 

[daselbee]

Re: Blocking Diodes, will this solve my slow mode situation

"to make a long story short there was a leak on the 1/4 fuel line going to some kind of addiative imput spot that has a red turn handle. At the three way fitting The 1/4 hose was clamped on with a zip tie. That connection was leaking fuel at high rpms when the fuel pressure increased."

I don't understand this. How can a leak at the primer solenoid input affect anything? When running, that fuel pump is putting out fuel PRESSURE...about 3-7 psi to feed the carbs, and that pressure is also at the primer solenoid input. So, NO AIR can leak IN. The fuel is under pressure. How can air leak in? Fuel will leak out for sure, but I cannot se how any air can be introduced into the system at the output side of the pump.

His primer bulb will not pump up and get firm, and while running, there will be a fuel leak, but air into the system? Please explain this.

 

[maui al]

Re: Blocking Diodes, will this solve my slow mode situation

for the above comment. Maybe I wrote it wrong or maybe you mis read what I wrote, but fuel was coming outof this 1/4 fuel line where it was tied into the fitting. It was like a litting boy pissing when the engine would be running or we would be pumping the primer bulb.

Is that what the thing with the red handle is called, "primer solenoid". So the fuel was leaking out of the 1/4 inch line feeding to the primer solenoid at the three way fitting.

I will make sure I stock some zip ties of all sizes on the boat, never can tell when they will come in handy again.

We do not have Tow USA on Maui. We are tow it youself or call a friend.