83 75hp Hard starting/idle warm or cold

[rufusj]

Hi,
I am hoping someone on this forum can help me. I wish my grandpa was alive :-( I could just ask him - he worked for Evinrude for 40+ years. I just purchased an 83 75hp. The previous owner ran out of patience, time and money trying to fix a hard starting issue. I am not a mechanic, but through this and other forums, I think I have it narrowed down to a carb/float issue, needle adjustment issue or a timing adjustment issue but I would like to narrow down what to buy next - carb kit or timing light. I don't know how to adjust the little screws if that is what it is. Or maybe there is something else?

The motor has good compression, good spark. The plugs, fuel lines, filter, and bulb are all new. The primer solenoid seems to work ok. On muffs the motor starts way easier presumably due to no back pressure?

Here is my starting ritual:
1. Pump bulb
2. Push in key and turn over
3. Motor tries to fire a couple of tries
4. Stops firing - just spins
5. I turn the red lever to manual
6. Turn over - tries to fire again but won't start
7. Turn back to automatic
8. Motor fires and starts otherwise repeat from 3
9. Idles rough - must keep idle high or dies
10 Engaging gear nearly kills motor
11. Once moving she runs great
12. I shut it off same problems to start again even fully warmed up
Thanks in adance

 

[HighTrim]

Re: 83 75hp Hard starting/idle warm or cold

If it has compression and spark, I would look to fuel delivery as you are.

Have you tried spraying pre mixed fuel from a spray bottle into the carbs, does that help? If it has been a couple years since a carb rebuild, it wont hurt either way to rebuild and bath it. The normal operating position of the primer solenoid is to have that red lever positioned over top of the solenoid and aimed at the other end of the solenoid, turned to its stop. Think of it as a choke. There is a very good thread in the FAQ section here on "Cold Starting Procedures", I will post the link below. This video may help with your carb rebuild. You are correct, outboards always react differently on the water due to the backpressure on the exhaust. Good luck.

"http://www.meegsonline.com/tmd/TMDsVideoChronicle2.wmv"

http://forums.iboats.com/showthread.php?t=225510

 

[Solittle]

Re: 83 75hp Hard starting/idle warm or cold

The only thing I would add to HighTrim is buy the OMC shop (not owners) manual. It has procedures, diagrams and pictures - get the parts catalog too as it has parts explosions diagrams as well as parts inf.

 

[tashasdaddy]

Re: 83 75hp Hard starting/idle warm or cold

i think i would check compression, just for kicks.

 

[rufusj]

Re: 83 75hp Hard starting/idle warm or cold

Thank you for the replies. I will give some of the suggestions from the other thread a try in the morning but I still have that idle problem. The video also will be very helpful if I rebuild the carbs but I would like to save that for last if I can - I am not very well equipped for that. I bought a book by Seloc - will look tonite for adjustment instructions that may help.

Two more quick questions if you wouldn't mind.

1. Why do you suppose switching to manual choke briefly and then back again helps the motor to start? (see step 5 in my original post) Without doing that, it is nearly impossible to get going. Does that help narrow it down at all?

1. What is the likelihood that timing or some little mixture adjustment screw is causing these problems rather than carb? I would go invest in a timing light if there is a good chance and I suppose a compression tester but don't want to go broke before I can buy the carb kits ;-)...

Thanks!

 

[jtexas]

Re: 83 75hp Hard starting/idle warm or cold

I don't see "lift hi-idle lever full up" on your list of starting procedures - makes a big difference. Make sure the timer base moves all the way to its stop when you advance the lever.

Does the choke (primer) solenoid 'click' when you engage it with the key?

How old is your fuel? Any water or debris in the tank?

I suspect you're idling on two cylinders. At idle, pull then reconnect the spark plug boots one at a time -- RPMs should be noticeably reduced; if not, that cylinder's not hitting.

Don't run the engine like it is anymore than needed for troubleshooting - any cylinders starving for fuel are also not getting oil.

What do the spark plugs look like after idling? Do they all look the same? Wet, dry, oil or carbon deposits? Are they champion QL77JC4 gapped at .030?

If your carbs need rebuilding, do that now, they could be masking other symptoms. carb kits about $12 apiece. Fixed jets - no mixture screws to fool with. Piece of cake. Aerosol carb cleaner makes an adequate substitute for compressed air in most cases. I like B-12.

I have that seloc book - you can get through a carb rebuild with it and this forum. Factory manual will pay for itself many times over, though.