1981 150HP Evinrude

[teamkl]

Hello all,

I have a 1981 150 HP Evinrude that has me totally frustrated. Sometimes is simply will not start. We have found a quick blast of starting fluid will fire it right up though. Runs great at the mid and top end. The carbs were just rebuilt, all fuel lines, fuel filters and fuel tank replaced.

My guess if fuel pump or primer system? The primer bulb is always pumped full. It likes to die at low idle while in gear also, such as first starting out or loading onto the trailer. But a blast of starting fluid will pick it right back up. Obviously that is very bad for the motor and not a long term fix. Any ideas?

Thanks for any insight you could give me.

 

[wilde1j]

Re: 1981 150HP Evinrude

First, I would only spray premix for testing. Ether has zero lubrication. It's quite apparent you have a fuel starvation problem. I would start by testing the fuel pump output with a gauge. Alternatively, you could disconnect the fuel pump fuel out line, crank the engine over (make sure it can't start). You should see strong fuel pulses. If not, replace or rebuild the fuel pump (if OMS/VRO, the fuel side is rebuild-able). If pump is OK, start looking for air leaks in the suction side plumbing (cracked hose, clamp not tight, bad anti siphon valve, cracked pickup tube, blocked pickup screen, etc.)

 

[jeffersondodson561]

Re: 1981 150HP Evinrude

Does this have a choke or enrichener? Did professional do carb overhaul did they: verify TDC sync and link carbs, set/check idle and wot timing?

 

[boobie]

Re: 1981 150HP Evinrude

Have you done a GOOD de-carb on this mtr lately??

 

[teamkl]

Re: 1981 150HP Evinrude

Guys, thanks for the responses. The carbs were rebuilt and a tune-up done last spring by the local Evinrude dealership. One thing I forgot about but remembered when you brought up timing.....on one run last year we lost all power and had to be towed back to the dock. After determining compression, spark and fuel where all happening we concluded it had to be timing. Talked to the Evinrude dealership and the suggested pulling the flywheel. We did that and discovered the keyway between the crankshaft and flywheel had sheered. The dealer said to simply replace this keyway and the motor should be back in time and ready to go. It did fire up after doing this but do you think that keyway sheering could be the cause of a timing issue now. Not quite sure how to check the timing on an outboard so haven't done that yet.

We contacted a different Evinrude mechanic last summer about our issues and he brought up the "link and sync" also. What exactly is this? Timing the carbs with ignition?

Last night I checked to make sure the primer solenoid was "clicking", it seems to be fine. Can you check to make sure it is working properly by pumping the primer bulb (pressurizing the system), disconnect the outlet hose of the primer solenoid, then push the key to activate the solenoid and see if fuel comes out of the solenoid outlet?

Sorry for the length of all this, just highly frustrated. This motor is on a bass boat and always seems to give us the most trouble at critical times, at tournaments (heading to weigh-in)!

 

[Fed]

Re: 1981 150HP Evinrude

Can you check to make sure it is working properly by pumping the primer bulb (pressurizing the system), disconnect the outlet hose of the primer solenoid, then push the key to activate the solenoid and see if fuel comes out of the solenoid outlet?

Yes but to get a good flow you will need a helper to maintain some pressure on the bulb. Once you let go of a pumped up bulb the system is no longer under pressure it's just full. Discounting the tiny bit of pressure the fuel pump diaphram my apply but that vulume would be gone in a heartbeat. I think you're on the right track here, blocked primer or blocked idle jets.
I hope you/they torqued that flywheel down right.

 

[emdsapmgr]

Re: 1981 150HP Evinrude

If the idle timing is too low, it won't idle. It should be easy to check the timing as you crank the engine. You can test for #1 and #2 cyls on that model. If it runs fine at top rpm it's not likely the pump. The carbs on that engine have special dedicated passages for the fuel when at idle and the butterflys are closed. If there is any debris or dried fuel on those idle passages or the idle jets, it won't idle. Once you crack the throttle, other jets start to provide fuel. It's one thing for the cold start solenoid to click, it's another to have it flow fuel. You might take the ends of the primer hoses off at the engine and push in on the key switch when the key is on. You should see fuel pulse from the small fuel hoses.

 

[SparkieBoat]

Re: 1981 150HP Evinrude

sounds like low speed jets clogged...DO NOT use starter fluid again or we will hang you by your toes and beat you with a string of catfish. LOL

 

[teamkl]

Re: 1981 150HP Evinrude

Update.....Fuel pumps, lines and primer solenoid all seem to be working correctly. So I guess the next step is to take it to the shop and have them check timing and sync/link.

 

[teamkl]

Re: 1981 150HP Evinrude

Update....it's currently at the Evinrude shop. Mechanic said the recirc valves are original from '81 and he can pretty much guarantee that is the problem, putting new ones in. Said he did a cylinder leak down test and the motor seems to be in great condition. Will send another update after a few test drives.

 

[boobie]

Re: 1981 150HP Evinrude

I read your orginial post and I can't see where recirc valves will cure this prob. Bad recirc valves will normally effect idle only. Not starting

 

[teamkl]

Re: 1981 150HP Evinrude

He has replaced the recirc valve and now has a "popping/kicking" problem at idle in the tank. Said he suspects a lean cylinder and is currently trying to find the culprit of that. Updates to come...

 

[SparkieBoat]

Re: 1981 150HP Evinrude

it never ceases to amaze me at how much professional mechanics just guess, instead of actually figuring out what is wrong. how they can get a repeat customer I will never know.

 

[teamkl]

Re: 1981 150HP Evinrude

Well this story finally has a happy ending. Took the boat out on Saturday and it ran like a dream! Started every time, idled perfectly, never died and loaded on the trailer with a lot of power. Gained 4mph on the top end (which could be attributed to the new Huster prop).

It is believed the problem was solved the 3rd time the mechanic had the carbs apart and "boiled" them in a cavitation cleaner. He said there are some small ports in the carbs that can't be cleaned any other way. As far as I'm concerned he did an amazing job, only charged us 4 hrs of labor and probably had 40 hrs into it, and he figured out the problem when other Evinrude mechanics couldn't. Very happy with the results!

 

[SparkieBoat]

Re: 1981 150HP Evinrude

well I am glad to hear the mechanic did not charge you for his guessing game. most will. So it shows that he is at least fairly honest. Now he has a little more experience and will know what to do next time. I think someone in post #8 told you that it was clogged carbs, specifically the smaller low speed passages. which appears to have been the problem.