15 hp Force oil loading at idle

pecheux

pecheux

Lieutenant Junior Grade
Joined
Jun 9, 2006
Messages
1,200
Good day, When trolling for a while the motor gets 'shaky' and produces more exhaust smoke. I beleve, and correct me if I am wrong, this is called "oil loading"
The plugs are new and checking them after a day out shows clean dry plugs with the right sandy color.

I can ajust carbs and it is set centered between lean stalling and too rich (half turn between each)

Using synthetic HPI oil at 55:1 ... would I need to use an oil that is for premix only that burns easier at idle in order to prevent this oil loading ? or use a leaner mix ?

Thank you for your feedback. and have a great day
 
O

Old Gamefisher

Seaman
Joined
Apr 20, 2009
Messages
51
Re: 15 hp Force oil loading at idle

Monsieur Pecheux,

I don't know if it was a typographic error, but you said you were mixing it at "55:1." I believe the correct ratio is 50:1, as it is in my 1990 Force 15hp. Also, although Amsoil (don't know what brand you're using) says you can pre-mix their brand of injector oil, I can't help but think that it's formulated specifically for injectors, and that there is a difference.

The problem might be that your carb idle jet needs cleaning.

Hope this helps.
 
P

pnwboat

Rear Admiral
Joined
Oct 8, 2007
Messages
4,251
Re: 15 hp Force oil loading at idle

At idle, the fuel tends to collect and puddle up in the engine. There are some one way drain valves that route this excess fuel/oil mixture back to the intake to be re-burned. These check valves sometimes get stuck and plugged up causing poor idle. I have attached a picture of a 1990 15HP. Not sure what year motor you have. Remove the drain valve cover (Item 18) and use some carburetor cleaner or similar cleaning fluid to clean the drain valves (Item 20). Make sure the screens (Item 19) are clean too.

http://www.crowleymarine.com/mercury_parts/1459/160.cfm
 
pecheux

pecheux

Lieutenant Junior Grade
Joined
Jun 9, 2006
Messages
1,200
Re: 15 hp Force oil loading at idle

Old Gamefisher said:
Monsieur Pecheux,

I don't know if it was a typographic error, but you said you were mixing it at "55:1." I believe the correct ratio is 50:1, as it is in my 1990 Force 15hp. Also, although Amsoil (don't know what brand you're using) says you can pre-mix their brand of injector oil, I can't help but think that it's formulated specifically for injectors, and that there is a difference.

The problem might be that your carb idle jet needs cleaning.

Hope this helps.
Click to expand...


Tx, Yes it is Amsoil HPI injector oil ... which they say can be used at 50:1. Perhaps it is "too much quality" oil to be used as premix since HPI will vary from 150:1 idling to 50:1 at WOT. I had in mind to rise the mix up to 60:1 as Rosco does.

Tried the Saber at 80:1 last year, the oil loading problem disapeared and idling was perfect ... but the motor had a different sound and so was the exhaust odor.

I could try it again, but after reading all the 'nays' about it on this board ... I m not sure it's the right thing to do.

Wish I could find a synthetic oil which would be designed for premix only.

Regards
 
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