1977 evinrude 85.... wont idle/run

woodsmithie

Cadet
Joined
Oct 18, 2008
Messages
8
I bought this boat a month ago and someone had reworked the heads, new carbs a new water pump... but i did not get to run it before i bought it....(really good deal)

I had to replace the water pump (it was melted, argh)... then it started OK, RPMs were high in start, shifted OK.

Put it in the water, started OK, but died when I tried to put it into gear... managed to get it home, in the water.

THE PROBLEM: Hard to start, then died after 5-10 seconds. (sounds like it is starving for fuel)

WHAT I HAVE DONE: New plugs, replaced 2 leaking fuel lines, made sure the fuel clamps are all secure, fuel filter screen is clean....Compression check (90,105, 95, 95).... Checked the rigging of the throttle ans start lever...(was bad)... rigged start lever, throttle and carbs according to the service manual.

Now the start RPMs are down to 1100, but it died shortly after starting (5-10 seconds) and i have to choke is to get it to start.

I am wondering if the fuel pump is bad?
Or I have an ignition problem?
Or should the starting idle be higher?
 

iwombat

Captain
Joined
Jul 12, 2006
Messages
3,767
Re: 1977 evinrude 85.... wont idle/run

You may have to bump the choke several times to keep it going until it warms up a bit. That 95-105 compression difference (on one side?) is borderline and would concern me. How does the plug look on that side - does it look steam-cleaned? The melted waterpump means someone ran it w/o water, and could also mean an overheat and a blown head gasket. Then again, it could just be a simple link-n-sync problem.

I think a spark test is next in order. You could also try pumping the bulb after starting and see if that solves the problem.
 

LiLGrady17

Seaman
Joined
May 1, 2008
Messages
67
Re: 1977 evinrude 85.... wont idle/run

I went through a new-to-me purchase this past year. Unless you personally knew the prior owner, do the carbs yourself to rule them out. I had junked up low speed jets. These motors can be a bear to start cold. Keep in mind it is Oct and it will take a while to get the engine up to temp. This week, I had mine running on the muffs, and it took 15 mins or more to get it running smoothly, fully warmed up & choke off. Hot Idle on the muffs should be 1100-1200.
 

woodsmithie

Cadet
Joined
Oct 18, 2008
Messages
8
Re: 1977 evinrude 85.... wont idle/run

well, i had to take a couple of days off the boat.. family things.

I checked the spark, OK at 7/16.

Found the air line from the case to the fuel pump was bad.. replaced it.

Replaced the fuel pump also.

I can now get it to run, but still not idle on its own.

It runs for about a minute with occasional chocking, but then it dies, and the fuel bulb is part full of air.

I checked and tightened the fuel supply lines, no help. pumping the bulb while it is running seem to have no effect.

now I am stumped......

I don't know that rebuilding the carbs would help my problem????
 

iwombat

Captain
Joined
Jul 12, 2006
Messages
3,767
Re: 1977 evinrude 85.... wont idle/run

After the engine runs a bit the bulb just becomes a wide part of the fuel line - it won't remain hard.

Honestly, I think your problem is dirty carbs. But, I'm still a little troubled by the compression difference on the one side. Once again - how do the spark plugs look on that side?

You might also want to go through the decarbonizing procedure and measure compression again - could just be caroboned up rings.

If you can eliminate a compression issue, it's time to tackle a carb rebuild.
 

bowman316

Lieutenant Commander
Joined
Oct 21, 2008
Messages
1,822
Re: 1977 evinrude 85.... wont idle/run

try increasing the idle by turning the screw at the linkage of the shift cables.

if you have a bad head gasket, there should be un-burned black oil running down the powerhead, down the outside of the lower unit.
This happened to me, and i changed the gasket,
not that hard, only a $20 part. And really easy to get access to, just 20 bolts holding it on.
The head gasket, keeps water from mixing with the fuel,
so that would lead to the fuel not burning all the way, and rough idle.
 

woodsmithie

Cadet
Joined
Oct 18, 2008
Messages
8
Re: 1977 evinrude 85.... wont idle/run

well decarbonizing the engine helped a lot..... I did it 2 times.... now the engine will idle with the run lever up (1200rpm).

Rebuilt both the carbs, found 2 idle jets totally plugged, and 1 of the jets damaged. installed new idle jets.

Engine now idles fine (950rpm) in run position, and 2000rpm in start.

Compression check is much better 105 on all cylinders.

The test drive was all good with the exception of there is almost now power in reverse, I am going to post this in a new message in the correct forum.

thanks again to all for all the help,:)
 
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