85 Johnson 150 Possible Power Pack issues

[MMPikefork]

Currently engine runs great but twice at WOT it died and when I cut the throttle back to idle it recovered. This has happen twice and always at WOT. Could it be a power pack going bad? In addition, I was looking at power packs and in the details section it listed a limit of 5800 I would assume this is RPM. Would this be correct? Any help with this matter would greatly be appreciated.

1985 Johnson 150 VRO

 

[jonesg]

Re: 85 Johnson 150 Possible Power Pack issues

Not power pack, thats fuel starvation at WOT.
Did the fuel bulb collapse?
if yes then theres a obstruction before the bulb,
if no then I'd be ordering carb kits and rebuild them.
Get the manual for it.
www.outboardbooks.com

 

[emdsapmgr]

Re: 85 Johnson 150 Possible Power Pack issues

Agree with Jonesg's diagnosis on a fuel issue. You can try contantly pumping the fuel hose bulb. That forces extra fuel into the carbs. If the engine runs fine at top end while doing that, likely weak pumps. The 5800 does indicate the rpm rev limit.

 

[MMPikefork]

Re: 85 Johnson 150 Possible Power Pack issues

Thanks for the info. But what would be the key difference between Ignition issues and fuel? In addition if it was fuel would it not do it all the time at WOT and would the Fuel bulb be collapsed? This issue does not happen all the time and seems to be more prononced when the water is choppy and at times may just feel a slight burp or miss. I have pulled the plugs and they look good no fouling. I Appreciate your advice

 

[Big flop]

Re: 85 Johnson 150 Possible Power Pack issues

You have two power packs? Unlikely for both to fail at once.
Check all ignition connectors & grounds (clean & tight)
Primer bulb check valves or anti-siphon valve are normally a
Consistent problem but can be a
Inconsistent problem
Also install a clear hose after fuel pump to check
for leaking into fuel system.

 

[jonesg]

Re: 85 Johnson 150 Possible Power Pack issues

Thanks for the info. But what would be the key difference between Ignition issues and fuel? In addition if it was fuel would it not do it all the time at WOT and would the Fuel bulb be collapsed? This issue does not happen all the time and seems to be more prononced when the water is choppy and at times may just feel a slight burp or miss. I have pulled the plugs and they look good no fouling. I Appreciate your advice

Again, if the bulb collapses the restiction is before the bulb.

Might as well start at the top and test the ignition,
get a $10 spark tester at auto store,
set gap to 7/16th inch and see if it will jump the gap.

 

[emdsapmgr]

Re: 85 Johnson 150 Possible Power Pack issues

Poor fuel delivery means the two pumps are unable to supply enough fuel to sustain continuous high speed operation. The engine will run fine at top end till the engine consumes the fuel in the carb bowls. The engine will slow down till the fuel pumps recover and refill the bowls-the engine will speed up again. The boat will run fine at top end again, then slow down as the carb bowls run out of fuel again. The process repeats over and over. You may not notice any problem at mid speed for some time till the fuel supply gets even weaker. That's the scenario for insufficient fuel delivery. Some potential causes: Weak fuel pumps. You could also have crud/debris in the anti-siphon valve on the fuel tank, which is restricting fuel flow. 5/16" fuel lines will restrict fuel flow-must be 3/8" fuel line on a V6. If you have an air leak at the fuel connector at the engine cowling, that can be the problem. (eliminate that hose barb and run the incoming fuel line direct to the upper fuel pump hose barb.) Did you double check to insure the two fuel pumps are the correct ones for a V6? Those pumps are different part numbers, and one is the upper, the other the lower. If the engine has a water separator added to the fuel system, remove that filter from the fuel system and retest the engine at full speed.