Idle speed adjustment

Hello everyone,

Please let me say thank you for all of the information on here as I am a new boat owner.

I had trouble with my 1993 60 HP merc jet outboard idling and I noticed that the throttle valves are closed at idle. So I adjusted the linkage to make the just slightly open. Well this has now made it idle ok if not fast. What I am wondering is I have noticed what look like screw in air bleeds on the sides of the carbs next to the idle mixture screws and is this how the engine gets its idle air quantity? I am not new to idle bleeds as I have worked with alot of automotive performance carbs that were equipped with them. And next question is if they are indeed that should I removed them and spray with gumout to clean them?

Thank you again

Michael

Re: Idle speed adjustment

First you do not adjust idle speed with the throttle plates on a outboard it is done with the spark advance now the engine synchronization is screwed up, first thing you need is a manual, it sounds like you are mechanical but don't understand the workings of a outboard so bite the bullet and save yourself some money and get a OEM manual. The screws you found on the top boss are float bowl vent jets, the carb float chamber is vacuumed at mid range to drop the fuel level too lean mid range for economy and to smooth the engine preformance the smaller the jet the leaner the mix.

Re: Idle speed adjustment

Thank you. I didn't adjust the timing I did see that as I was investigating the throttle linkage. I loosened the linkage at the carbs as each are separate but I do understand what you are saying. Where is a great place to find a manual? I am asking because this being a factory jet drive, it seems that dealers have no clue. Just my findings with replacing the entire cooling pump. Turns out it is the same as the Big Foot series, if that helps anyone that has one.

And again thank you for the response.

Michael

Re: Idle speed adjustment

Mike I would start on ebay as the OEM manuals are quite expencive, but the aftermarket are incomplete on a regular O/B so you can imagine what they would be on your jet. I was checking and can't find a 60 jet listed, I find a 60 bigfoot with a jet called a 45 jet and a 65 jet that is a 90HP powerhead so I don't real know which manual you need.

Re: Idle speed adjustment

That is the one I would need ( 60 hp big foot) that is how they are rated. There is approx. 30% loss between powerhead and jet drive. 60/45 jet is what I have. Thanks for all the info I will def check it out now.

Re: Idle speed adjustment

When you get your manual look for the section that tells you how to do a link & sync. You will quickly find that the throttle valve are suppose to be closed. Just be sure to do the procedure in the order they say.