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77 Evinrude 85 h.p , will not idle

Na8en101

Regular Contributor
I recently refurbished my boat 1977 apollo 660 it was running fine with the muffs on , 1977 EVINRUDE 85 hp. Went to launch it yesterday, right next to my slip. The only way I could get it to run was with the warm up all the way up high rpm and slowly bring down. If I try to put it in idle to shift gears it dies almost instantly . I have replaced all the plugs all the lines, I made sure the gapping was right . Should I rebuild the carb? I have a kit coming on monday 8/19/20, is there anything I should check in the meantime? It has been quite some time since I've had engines with carbs , went from none to three in a week . And advice it help would be greatly appreciated
 
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They all run " fine " on a trailer.-----Start with a compression test.----If that is ok then do a " maximum intensity " spark test.----Good spark will jump a gap of 3/8" with ease.
 
Don't be too hasty. Sounds to me like the idle speed may be set too low. It must be set with boat launched, not on a trailer. But first, they all will snort and conk out if you don't give it a brief bit of time in warm-up positon to ----well "warm up". Secondly, disconnect the throttle cable at the motor and set the idle speed adjustment. Then install and adjust the throttle cable. Always adjust the control to fit the motor, never adjust the motor to fit the control.
 
You state "It has been quite some time since I've had engines with carbs , went from none to three in a week."

Three engines in one week... One engine with three carburetors??

Model number of this engine?
 
Lol no three completely different engines , snowblower. pressure washer, outboard , it is an 1977 85 hp evinrude model 85799S
 
I have the clymer manual for the engine because I always purchase one for the engines I have to maintain, it's just clymer manual vs. Experience, experience always wins, so I figured I would ask some people that have better knowledge than me on this
 
so today once it stops raining and the wife comes home to keep an eye on the kids I'm going to rebuild the carbs, and then tomorrow link and sync, and decarb, first I have to bucket out water from the cover that came loose and reconnect the battery so the bilge pump turns on, if anyone has any other suggestions I would appreciate it
 
so I rebuilt the carbs got it running couldn't get it to idle until i set the linkage to were the idle screw wasnt even touching the motor , took it for a run around the river put it in neutral and the idle is really high , idk why the idle is so low when i have it docked at the pier but so high when I'm out on the river , it wouldn't make me so nervous if it didn't shift so damn hard, i know the water is pretty low at the pier idk if that would have something to do with it , I have a replacement "air silencer" gasket coming soon,if anyone has any ideas please let me know it is much appreciated I'm not a boat guy
 
so I took the boat out with the family down the river onto the lake I think I have to replace the impeller I'm pulling the boat out tomorrow, as I would increase speed the over heating alarm goes off , I have to put the boat back into neutral until it goes away , idk if this indicates a water pump and impeller, I also have to add fluid to the t and t unit with higher speeds it lowers by itself , if anyone has any input I would appreciate it
 
I strongly suspect that what you think is a tilt/trim unit is actually the early model "Tilt" only setup. If so, that is designed just for raising and lowering the engine when the engine is NOT running. It will not hold pressure while underway.

Your explanation of the overheat alarm indicates that either the water pump needs work... OR... the engine is not matched for the transom. The anti cavitation plate just above the propeller should be approximately 3/4" below the bottom of the keel at the transom (in that area).

Why it would idle high at the dock and not in deep water is a mystery for the time being.

Did you adjust the carburetor high and slow needle valves as mentioned earlier?
 
the t&t has three rams two smaller ones on the outside , one bigger one directly underneath the outboard, I just bought a new pump kit and screen that I will be installing , when I rebuilt the carbs it appears as if they were never touched or was a very long time ago, so I'm assuming nothing has been touched since late 70s early 80s, there is not any fuel mixture screws on the carbs , the engine and transom and boat are all original from factory, so my plan is to replace the water pump clean up whatever I can replace the screen, add more fluid to the tilt and trim, and screw around with the linkage, because it does not make sense to me why I had to adjust the linkage from the control box to the engine to where the idle screw will not even touch the motor block just so that when the warm up switch is down it doesnt shut down, I am sorry if anything I am saying does not make sense if you need me to elaborate please tell me and thankyou
 
the t&t has three rams two smaller ones on the outside , one bigger one directly underneath the outboard, I just bought a new pump kit and screen that I will be installing , when I rebuilt the carbs it appears as if they were never touched or was a very long time ago, so I'm assuming nothing has been touched since late 70s early 80s, there is not any fuel mixture screws on the carbs , the engine and transom and boat are all original from factory, so my plan is to replace the water pump clean up whatever I can replace the screen, add more fluid to the tilt and trim, and screw around with the linkage, because it does not make sense to me why I had to adjust the linkage from the control box to the engine to where the idle screw will not even touch the motor block just so that when the warm up switch is down it doesnt shut down, I am sorry if anything I am saying does not make sense if you need me to elaborate please tell me and thankyou

I would check fuel line pressure first. After spark strength test. Before more elaborate fuel pump rebuild. If it's running ok on high rpm, it is getting adequate fuel under high demand.
Carborateur linkage adjustments may be the issue m.
 
I also just replaced all the fuel line , and have a new fuel pump on the way, the fuel line were such garbage that when I took the carbs off and tried to disconnect they basically fell apart , had to use razor blade to get the rest off
 
Did you adjust the carburetor high and slow needle valves as mentioned earlier?

Disregard the above previous mention. There are no such adjustments on those carburetors... A entry designed for a different thread. Apparently forgot where I was... a senior moment (sigh).
 
I also just replaced all the fuel line , and have a new fuel pump on the way, the fuel line were such garbage that when I took the carbs off and tried to disconnect they basically fell apart , had to use razor blade to get the rest off

I would then look at Timing. If that needs tweaking at slow speed. Especially if the bright spark is jumping 7/16th gap (several times the spark is there but it has already jumped frayed spark plug wires and may be a good idea to replace the spark plug wires or at least check them for resistance) and if fuel supply seems ok as it is more of issue at high RPM where it gets stressed out.
 
it's all good, I'm just appreciative people are helping me, figure whatever mess I have or have caused, I've got to fix the mother inlaws garbage disposal, then will be pulling the boat out and taking off the lower unit , to see what Is going on in there, once I put on the new water pump , and fuel pump , and replace one more fuel line, I will start screwing around with the idle and linkage , because it still does not make sense to me, the linkage from the control to the engine I have tightened as much as possible and the idle screw stays about a half and inch away from its stop. if that makes sense at all, I really hope I have trim on my boat otherwise I dont know what that 3rd ram is for , and the seller kept telling me about having to adjust it to plain out , again thanks for any suggestions / knowledge you guys can provide
 
Your description of the PTT unit.... Yeah, that's a Tilt/Trim unit.

Garbage disposal problem? (We're experienced in many areas!) :cool:
 
Post results of a compression test.

It seems that it is running fine at high rpm. so Compression test may not be the culprit for stall at idle. Stall at idle could result mostly by inadequate momentum or timing of the blast in chamber to continue the rotation of the crankshaft. Inadquate fuel in chamber at the idle, or inadequate or ill timed spark seems to be the specific culprit for the specific stall at the idle.
 
Na8en101... I see that the compression psi readings and the condition of the spark have been requested... BUT... I don't see any reply as of the 20th post/reply.

Those are the two main areas of concern before dwelling deeper into a problem.

First... Remove "all" spark plugs, then check the compression. What are the psi readings of the individual cylinders? Note that standing in back of the engine, facing the spark plugs, the cylinders are numbered as follows:

2.....1
4.....3

Second... Check the spark with a tester whereas you can set a "Air Gap" of 7/16". The spark should jump that air gap on all cylinders with a strong blue lightning like flame... a real SNAP! Does it?
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(Spark Tester - Home Made)
(J. Reeves)

You can use a medium size philips screwdriver (#2 I believe) inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark or build the following:

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:

..........X1..........X2

.................X..(grd)

..........X3..........X4

This can obviously be modified to a 6 or 8 cylinder setup tester.
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the 20th reply was this morning lol I can get it either later today or tomorrow, I do have a spark tester I dont think I can adjust the air gap I would have to check , or I'll make the homemade one and compression tester
 
ok so I purchased a compression test and a spark plug tester I will be pulling the boat out today as it is my only chance I'll have. and I will get all the numbers for you guys, I also purchased a timing light if it comes down to that, but I will be replacing the water pump and such and the fuel pump
 
ok just did compression test 1,3,4 are at 95 psi 2 is at 100. I did a spark test 1,2,3 passed 4 would spark intermittently I am going to include some pictures of the spark plugs because they are only a week old and they are dirtier then ever and also some pictures of the engine in case you guys see something I do not like where the idle screw is pushed out too because of how I had to tighten the control linkage to get it running20190823_132841_compress4.jpg20190823_132905_compress93.jpg20190823_132921_compress78.jpg20190823_132928_compress86.jpg20190823_125743_compress21.jpg20190823_132826_compress13.jpg
 
There are 2 wee covers on each side of the block.----Held in place by 6 screws each.----Remove them to look at pistons / rings.-----Compression numbers tell me that is your next move !!
 
I may be wrong but I am thinking it is a timing issue or coil for cylinder 4 , when I ran it to put it on the trailer today is seemed to run good except for the high idle and hard shifting like I said I had to adjust the linkage as much as possible to keep it running plus there was crap gas I tried to get all out. I should also probably decarb that might help
 
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I'm willing to try anything you guys suggest and I appreciate it I think I'm making a big issue out of something simple
 
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