'69 Evinrude 9.5 HP Sputters at Idle and Low Speed

[bradford0113]

First time out this year and motor is sputtering at idle and low speed out of the dock. Opening the choke seemed to smooth it out enough to get me out onto the lake. Once in open water, it ran great at WOT with the choke closed - went about a mile. After stopping and fishing for about an hour, it was the same scenario back to the marina. Once in the marina, it sputtured and died and would not start again. Before pulling out, it started one more time, but then sputtered and died again at the low idle speed.

Last spring I completely overhauled the fuel pump and carbureter and installed new plugs and this motor ran great all summer. This year I am having these problems first time out. Any ideas on where I should begin troubleshooting? I would like to think that it's not fuel related because of the work that I did to the fuel system last year. If it's an electrical problem, is it possible to run great at WOT but not at idle? Any help or suggestions will be greatly appreciated.

Thanks
~Brad

 

[dew2]

Re: '69 Evinrude 9.5 HP Sputters at Idle and Low Speed

If it sat all winter the carb could be gummed up,That would be where I'd start clean it out good.But first check the fuel lines for leaks and drawing air.

 

[bradford0113]

Re: '69 Evinrude 9.5 HP Sputters at Idle and Low Speed

When you say "clean it out good," does that mean completely disassembling again for a cleaning or is there a method of "cleaning" without disassembly? As you can tell, I'm not very experienced in this field.

 

[AlTn]

Re: '69 Evinrude 9.5 HP Sputters at Idle and Low Speed

on the ignition side...look down inside each plug boot for corrision around the spring that snaps over the sparkplug end...you can pull the boot off the plug wire and spring after wd 40'ing it...it'll be tight and takes some workin', but once off.. trim about a 1/2" off the wire..then cut the insulation back enough so the wire ends will touch the wire coil when the coil wire spike is reinserted, just to give it more area of contact < you'll see when you pull the plugwire out of the boot>...new boots and coils from the dealer are about $6/ea....be sure to clean and adjust the points..if the plug wires are old and stiff...you might want to consider replacing them...they are wire core...from the dealer not much per/foot..

 

[dew2]

Re: '69 Evinrude 9.5 HP Sputters at Idle and Low Speed

When you say "clean it out good," does that mean completely disassembling again for a cleaning or is there a method of "cleaning" without disassembly? As you can tell, I'm not very experienced in this field.

Yes their real simple carbs and easy job for what it can accomplish.
Heres a link to parts/schematic views of that motor
http://www.crowleymarine.com/johnson-evinrude/1750.cfm

 

[bradford0113]

Re: '69 Evinrude 9.5 HP Sputters at Idle and Low Speed

Thanks dew2. I'm already familiar with the carb because I rebuilt it last spring. I guess it wouldn't be too difficult to remove and clean since I've already done it before. Is it okay to assume I don't need to completely rebuild again since it only has about 20-30 hours on it since the last rebuild exactly a year ago?

Regarding ignition... I've never had the flywheel off to even inspect the coils, points, etc. so i should probably do that too. Is it possible to pull the flywheel on this motor without any special tools?

 

[bradford0113]

Re: '69 Evinrude 9.5 HP Sputters at Idle and Low Speed

If it sat all winter the carb could be gummed up,That would be where I'd start clean it out good.But first check the fuel lines for leaks and drawing air.

I'm thinking you called it dew2! I took the carb apart last night and I can't believe how gummed up it is since I had just rebuilt this carb last spring. I could literally see big blobs of goo in the larger ports so I can only imagination how plugged up the smaller ports must be. It's been soaking in carb cleaner overnight and I'll be putting it back together this afternoon.

I think I also want to do a de-carb on this motor according to the instructions in the Top Secret File. Any reasons why I should or shouldn't do the de-carb?

Thanks
~Brad

 

[kbait]

Re: '69 Evinrude 9.5 HP Sputters at Idle and Low Speed

Decarb never hurts, and often helps noticeably.. I do one every season if heavily used (15hp).

Replace the 5/32" fuel line from fuel pump to carb, in case it's ethanol-eaten on the inside and sloughing off into your carb.. no screen after fuel pump. Nothing like clogging a freshened carb in 7 seconds.. (been there.) And run out/drain your carb bowl before storage.

If you can get consistent 1/4" blue spark from each lead, you're good to go. Good luck!