30 hp Honda idle problem

[cn2bakers2]

I have a 1999 Honda 30hp.Since new it has had this problem.After I run at wide open throttle for a while and I stop to slow troll it takes the motor about five minutes to slow down to trolling speed. This is hard on the gearbox if I need to make a shift during this time. Any advice would be appreciated. I have had the carbs synchronized.

 

[myles carey]

Re: 30 hp Honda idle problem

My first thought is throtle linkage.can you close the throtle by hand?maybe it needs to be oiled.

 

[cn2bakers2]

Re: 30 hp Honda idle problem

the linkage is properly adjusted. Carb cam is bottomed on idle screw.

 

[Skinnywater]

Re: 30 hp Honda idle problem

Not sure on your 30hp. <br />However,check to see if you have a vacuum dashpot (acceleration device/diapham assembly)connected to your carb linkage. This dashpot is to be adjusted after adjusting idle speed. Inline with the vacuum hose to it is a check valve. Check that is connected the correct way, it has an arrow. Check that it is working properly.<br /><br />Your more recent post states your dealer said this was normal operation. Find another dealer!

 

[cn2bakers2]

Re: 30 hp Honda idle problem

I have had a chance to check the dash pot and it is set correctly according to my honda repair manual. Could valve adjustment cause this when hot. Motor has about 300 hours on it and 80% of that time is slow back trolling. I don't thinkthe valves have ever been adjusted. Dealer never mentioned it anyway.

 

[cn2bakers2]

Re: 30 hp Honda idle problem

Skinnywater,just what is the purpose of the dashpot assy. I have checked the adjustment but the way it is set up I don't understand what it is supposed to do. I am an auto mechanic and know that on older cars it was to keep the throttle plates from snapping shut. But the way this is hooked up I can't see that it does that.

 

[Skinnywater]

Re: 30 hp Honda idle problem

Valve adjustment won't cause your particular complaint. Adjust them anyhow they're overdue. Adjust the cambelt while your at it, it's overdue also.<br /><br />Check the dashpot with the check valve installed with a vacuum guage. If it is failing it can cause your complaint.

 

[cn2bakers2]

Re: 30 hp Honda idle problem

I will be looking at this motor this weekend will keep you posted as to what I find.Thanks for advice on the dashpot.

 

[cn2bakers2]

Re: 30 hp Honda idle problem

I had a chance to work on this problem over the week end. I adjusted the valves and installed a water seperating filter. Also took a very close look at the dashpot. It is hooked up with the arrow pointing in the right direction according to my honda manual.Also checked it with vaccum and it is working fine.Still have high idle speeds when engine is hot.

 

[MajBach]

Re: 30 hp Honda idle problem

just a semi educated guess: could the carbs need syncing?

 

[cn2bakers2]

Re: 30 hp Honda idle problem

The carbs were just synced by Honda dealer 3 weeks ago.