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87 Evinrude 150 with odd problem

twomanytoys

New member
I sold a boat to some friends

I sold a boat to some friends and they are having a problem with the engine. Here is what is going on.

The engine will run and idle all day long with no problems. Once you get the boat on water and get it under a load after a few minutes it will just stall. Once it stalls it has no power. No power meaning no trim or even starter. If you let it sit for about 5 min it will start up like nothing happend. Then after a few min it will do the same thing. Once you do get it started it will run fine at lower rpm's but once throttled up under load for a bit it will lose all power and stall.

Anyone have any suggestions why this would happen or what I can look for? They are not feeling too good about this buy now and they are getting frustrated with me. I am a certified auto technician so I know my way around most engines but I dont know anything about outboard electrical. I was thinking maybe the stator was going bad and overcharging everything causing the engine to stall and losing power to everything else.
 
"Apparently there are two prob

"Apparently there are two problems as having voltage to the ignition switch to supply power to the starter circuit has nothing to do with the ignition problem. That engine would run with nothing attached to it excepting the fuel supply, that is if one is capable of cranking it over by hand with a starter rope.

The no voltage, power to the PTT assy or starter problem could simply be a loose or tight but dirty connection at some point. Remove and clean thoroughly all cables/wires pertaining to the starter circuit. This means at the battery, starter solenoid, powerhead ground, the electric starter, and the ignition switch, also at the battery switch if one exists.

You said nothing about having the power fuse blow so I'll say nothing about possible shorts.

The engine running and stalling problem. You said nothing about any warning horn alarm sounding. If there was one, see below. If the carburetors were fouled, the engine would tend to stall just as soon as the throttle was applied. Stalling, having the enge stop running after a few minutes is usually due to a faulty fuel pump, a air/fuel leak at some point in the fuel supply (pump draws air), or a fuel restriction such as a sticking anti siphon valve, explained as follows below.

(VRO Horn Warnings)
(J. Reeves)

NOTE: I retired around 1991/92. Possibly some of the later V4 engines and others may also incorporate a fuel vacuum switch that would enable a fuel restriction warning to sound as mentioned below, an unknown factor to myself.

1 - A steady constant beep = Overheating - The V/6 engines, possibly some others, have a fuel restriction warning which is also a steady constant beep.

2 - A beep every 20 or 40 seconds = oil level has dropped to 1/4 tank. (Late model engine = Every 40 seconds)

3 - A beep every other second = VRO failure, air leak in oil line, oil restriction, (anything that would result in a lack of oil being supplied to the engine).

NOTE - If the warning horn is the black plastic (overpriced) three wire type horn, the warning horn should beep once when the ignition key is turned to the ON position. If it does not, it is either faulty or someone has disconnected it (a stupid move!). At any rate, if it does not beep which indicates that the horn is non functional, find out why and do not run the engine until the problem is corrected.

When time permits, visit my store at: http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store

(Testing Warning Horn)
(J. Reeves)

On VRO equipped engines where the VRO automatic fuel/oil setup is still being used, make sure that all components are connected as required. This would include the VRO pump wiring harness itself, the oil tank wiring, the overheat sensor(s), and if so equipped.... the vacuum switch that is standard to many V6 & V8 engines.

If the VRO automatic setup has been eliminated and has been disconnected properly, and the fuel and oil is being premixed, make sure that the overheat sensors are still connected, and the vacuum switch if the engine is so equipped.

On engines prior to 1984 which have no VRO setup, ignore the instructions pertaining to the VRO components, etc above.

Turn the key to the ON position (Engine Not Running). Find the TAN wire at the cylinder head(s), then ground out the portion of that wire that is part of the engine wiring harness. If that Tan wire connector has the knife type connector where as it is exposed simply by sliding the rubber insulator back, it does not need to be disconnected.

Grounding that TAN wire should cause the horn to sound. If it does not, find out why as that's the only warning you'll receive should the engine overheat or have some portion of the VRO system fail, or have the engine encounter a fuel retsriction if it is equipped with a vacuum switch.

When time permits, visit my store at: http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store

(Fuel Anti Siphon Valve)
(J. Reeves)

Many of the later OMC V/6 engines incorporate a fuel restriction warning via a vacuum device attached to the powerhead. If the engine overheats, or if you have a fuel restriction, the warning is the same.... a steady constant beep.

NOTE... Only the V/6 & V/8 engines have the above "Fuel Restriction Warning". The warning horn will not sound on the other models.

The fact that a engine is not overheating, but the warning horn sounds off with a constant steady beep, and that the rpms drop drastically would indicate that the engine is starving for fuel due to a fuel restriction. Check the built in fuel tank where the rubber fuel line attaches to the tank fitting. That fitting is in all probability a "Anti Siphon" valve which is notorious for sticking in a semi closed position. It will be aluminum, about 2" long, and the insides of it will consist of a spring, a ball, and a ball seat. If this valve exists, remove it, knock out those inner components which will convert it to a straight through fitting, then re-install it. Hopefully that cures the problem.

The above procedure will cure a restriction problem with the anti siphon valve as stated. BUT, it may also allow fuel to drain backwards to the fuel tank when the engine is not running (siphoning backwards) due to the fact that the carburetors/fuel pump etc are higher than the fuel tank. This condition is not an absolute as the valves in the fuel primer bulb usually prevent this backwards siphoning problem. However.... if this does take place, the cure would be to install a new anti siphon valve.

When time permits, visit my store at: http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store"
 
"Joe
thank you for respondin


"Joe
thank you for responding. I have read alot of your posts and take in as much info as I can to help diagnose the problem. I too thought it was 2 seperate problems but what gets me is that they both happen at the same time every time. I have replaced the battery and cables are all good. If I let it sit for a few minutes everything comes back to normal. It starts a little slower but it still starts. Also if I just cruise at lower rpm's it runs fine and does not stall and all power is there. Once it stalls I lose everything for a few minutes. I will check the anti siphon valve and all fuel related hoses, valves etc...Would it hurt the engine to have it running on a hose and in gear at higher rpm's to try to duplicate the problem? I am not close enough to water to diagnose the problem in water. Everything is being done in my driveway. Also could it be some kind of bearing in the lower unit locking up and stalling the engine?"
 
"On a hose/flushette, it is no

"On a hose/flushette, it is not wise to have the engine turning up a high rpm. The reason being that there is no back pressure on the exhaust system nor the propeller. You would be inviting a runaway engine, similar to a runaway prop/engine on a aircraft. Regardless of the throttle setting, the engine would increase its rpms. By the time you figured out how to shut the engine down, connecting rods would be flying out the side of the crankcase.

You mention a scenario of a bearing locking up. You've made no mention of having the engine lock up...... lock up indicating that the engine has seized, unable to turn the flywheel either by the electric starter or by hand pressure. Is that engine actually seizing, locking up..... then five minutes later (as indicated in your first post) it frees up and can be cranked (flywheel can be rotated)? If so, this is not stalling, this is a seizing up problem."
 
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