9.9 Seahorse runs lean

[Autotech1]

I working on this motor for a coworker. He was running it with the choke pulled to get around. Model# 10R77A, SER# E4634748. Its been a year since he ran it, but I got it fired today. With the low speed nob at full rich, and the choke pulled halfway, I could get it to idle for ~30 seconds. Ive since disassembled the carb, cleaned, and reassembled, it was already remarkably clean inside. I'll run it tomorrow. My worry is that it was so clean I think it might be a crank seal issue or something else. I'll perform compression test tomorrow and post results. Any Input would be greatly appreciated.

 

[Rick.]

Re: 9.9 Seahorse runs lean

Based on what you know I think your on the right track with the carb. Best of luck. Rick.

 

[Autotech1]

Re: 9.9 Seahorse runs lean

I fired it up and it runs great now. I'm going to replace the prop shaft seals now, what gear oil is recommended?

 

[Vic.S]

Re: 9.9 Seahorse runs lean

Any high viscosity ( around sae 80W90) outboard engine gear oil.

 

[Autotech1]

Re: 9.9 Seahorse runs lean

Determined the seals are fine, just exhaust oil.
Replaced Plugs with NGK 4122 BR7HS, anyone have trouble running NGK in Jonnies? I know NGK is OEM for Nissan, Honda, and Stihl products and I'll generally swear by them.
Typically I swear AT Champion, but this could be case of a motor being built around a plug.

 

[Daviet]

Re: 9.9 Seahorse runs lean

Champion plugs are the OEM plugs.

 

[northwoodslivin]

Re: 9.9 Seahorse runs lean

the BR7HS's are a resistor plug and are not recommended for the ignition system of these motor's. I am not positive what plug this motor takes, but I am assuming the same seeing that I had these BR7HS plugs in my motor when I bought it "thankfully they we're just put in by the owner"

Anyway, they are now replaced with the proper plugs "Champion QL77JC4" Always run Champions in a johnnyrude motor if you can.
By the way, switching to the proper plugs made a big difference in the engines operation.

 

[Autotech1]

Re: 9.9 Seahorse runs lean

From what Ive read here, the Q in QL77JC4 indicates a "noise suppression" resistor plug, just like the BR7HS. I'm not worried about hurting the ignition, more about hampering the performance.
This motor actually had stickers on the plug wires recommending L77J4 or M40FFX, but they seem to be discontinued. another member here recommended QL77JC4 or QL82C, but NAPA had none of the above in stock.

 

[northwoodslivin]

Re: 9.9 Seahorse runs lean

I will cut and paste info that was given to me by Vic, trust me those plugs are not recommended

Regarding the plugs . The Champion Q series plugs are inductively suppressed. The NGK equivalnt is BZ7HS ( or BZ7HS-10 which is supplied gapped to 1mm.)

B7HS (-10) would be suitable as they are equivalent to L77JC4.

Avoid resistor plugs such as NGK BR7HS as they are not suitable for OMC CD ignition. Although frequently listed and sold as equivalents to the Q series they are not!

Recommended plug gap is now 0.7 to 0.8 mm
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[Vic.S]

Re: 9.9 Seahorse runs lean

From what Ive read here, the Q in QL77JC4 indicates a "noise suppression" resistor plug, just like the BR7HS

Wrong I am afraid.

The Q denotes a low resistance Inductive suppressor

You should not use a resitor plug with OMC CD ignition . If you must use an NGK plug use one without suppression. Or an NGK with inductive suppression.
B7HS is the equivalent of the unsuppressed L77JC4 but the equivalent of QL77JC4 is BZ7HS

Inductively suppressed plugs are also recommended for all engines with VRO and OMS systems

For an explanation see http://members.iinet.net.au/~pauldawson/iame26-spark-plugs.PDF


Beaten to my own info by Northwoodslivin Ive added the link this time

 

[northwoodslivin]

Re: 9.9 Seahorse runs lean

I figured you would chime in lol. I cut and pasted some info you gave me a while back above your post.

By the way, those plugs are amazing!

 

[Autotech1]

Re: 9.9 Seahorse runs lean

Thank you for the replies Fellas, I will call Napa and see if they have the
B7HS or BZ7HS in stock.

 

[northwoodslivin]

Re: 9.9 Seahorse runs lean

No problem But if you can get the Champions do so
GL

 

[Autotech1]

Re: 9.9 Seahorse runs lean

No problem But if you can get the Champions do so
GL

I got the B7HS plugs and installed. They didn't have any Champs in stock, and NAPA is the only source in BFE (AKA Reedsport OR).