Help diagnose alarm and stall - '93 150 Johnson

[ab1]

'93 150 Johnson 150 GLETR

Had this boat for about a month now and everything has been pretty solid. Been out 4 times with only one issue. When I first had it out it stalled at WOT. At WOT, boat would stall, surge, stall, surge before finally coming to rest. No alarms. Pumped some old gas out, replaced gas, replaced fuel filter and all was well until this weekend. That happened only once and I've had it out three times since no problem.

This weekend cruising at near full throttle and did the same stall, surge, stall, finally die. This time it didn't start back up right away but finally did after 20-30 minutes of sitting and trying to crank it. I did pump the gas tank out a couple of weeks before as mentioned above but I'm guessing there was still some 1-2 year old gas from previous owner at the bottom of tank. I've ran probably 30 gallons through it. Finally got it started and it ran fine.

The next day I was at idle and twice got a steady alarm. Immediately shut down, fished for a bit, and it started right back up. Steady alarm should indicate overheat or fuel flow restriction. Engine didn't feel hot and I could touch the block. Again, we were just idling around.

What should I start to look at?

 

[jonesg]

Re: Help diagnose alarm and stall - '93 150 Johnson

What did you do to it when you bought it?
Did you empty the oil tank, sometimes there is water beneath the oil...
is it still using the vro tank or do you premix fuel/oil. ?

Did you install a water seperator yet?
With todays fuel its important to get the water out.

Surging sounds like its leaning out, did you try pushing the key to choke when it surges?

Did the fuel bulb collapse when alarm sounded?
Is the tank vent free flowing to allow air into tank?
Pump the bulb firm and look at the fuel line with a flashlight, look for connections that are damp or leaking fuel all the way to the carbs.
Check around the seals of the fuel filter between the carbs and the carbs themselves.

If you can't find anything and don't know the service history order carb kits and rebuild them, simple DIY job. Carb kits avail here on iBoats, $22 ea.

You really need to go through the engine from plugs to prop, have you checked the gear oil? if it has water in it you can easily ruin the gears before you know it.
Did you clean the prop shaft for fishing line yet ?
Does it pump water good ?

 

[ab1]

Re: Help diagnose alarm and stall - '93 150 Johnson

Thanks for your reply...I've answered a few questions below. Do you tend to agree that this sounds like a fuel issue?

I didn't do much when I bought it. Drained as much of the gas as I could and it ran really strong. Didn't seem to have any issues I needed to fix. I did replace the fuel filter.

It still has VRO and I have verified that it is pumping but did not change out the oil.

No water seperator yet, but I will get one.

I haven't tried pushing the key when it surges. It has only happened at WOT...surges once or twice and then dies. I was more concerned with keeping control of the boat but will try pushing in the key. Would this indicate bad fuel flow? Where? Fuel bulb did seem softer after the alarm. Yes, tank vent is free flowing.

It does seem to pump water very well and has a strong stream. I did change the gear lube and replace o rings on both plug screws.

Thanks for any help you can offer. I plan to clean the carbs and then replace plugs. Would you start with this or go ahead and rebuild them?

 

[mikesea]

Re: Help diagnose alarm and stall - '93 150 Johnson

a quick way to Dx if its a fuel tank vent is to loosen the fill cap ,that will allow the air to get in ,if the squeeze ball goes flat when it is happining,your problem is before the ball.there is an anti syphon valve(sometimes its taken off)in the unit where the fuel leaves the tank,it might get dirty from crap in tank or sometimes if someone uses different mtals like brass and aluminum ,you get a corrosive reaction ,which can plug up the system,if you have access to a portable gas tank,you might bypass your fuel system to help dx.Check any inline fuel filtes for dirt

 

[ab1]

Re: Help diagnose alarm and stall - '93 150 Johnson

Thanks! I'll definitely check into that. If you guys have any other opinion on the original post, please contribute. I've been on this site for about a month now and chime in when I can so hope to be a good contributor. This issue just kind of has me stumped on where to start.

 

[jonesg]

Re: Help diagnose alarm and stall - '93 150 Johnson

Yeh but spark issues sound like fuel issues and vice versa.

The alarm says fuel delivery though.
Carbs don't respond much to exterior cleaning, using sprays etc,
they require removal and new parts, run wore through the jets to clear them, then spray. Its not difficult at all.
You have the plastic carbs so you can leave the throttle body on the block.

Primer bulb is supposed to go soft, not flat. Sounds like yours is ok as far as plumbing up to the engine.

Check the recirculation tubes , they have to be clear.
Fuel pump is powered by a vac line from the block, make sure that line isn't leaking, a loose connector there can be a big problem. Theres a vac check valve in the crankcase and the hose leads to the pump.