8N not throttle response

[powrguy]

Well, my 8N (about a 1951 model, SM distributor) all of a sudden has no throttle response. It will start, but barely runs, and does not increase speed when throttle is advanced. Yes, I checked all the linkages and fuel flow to the carb, and they are apparently normal.

I checked compression, and all cylinders are 90-95psi. My thought is that this indicates valves are closing okay, and no head gasket leak (no water in oil, oil is clean and normal level).

It almost acts as though it may be out of time, but it starts, and there's no back-firing.

Could it be a cam gear/governor gear problem? Don't know where to look next, so anyone that may have had similar problem could chime in?

thanks

 

[R Geiger]

Fuel flow to the carb means little, you need to check the flow thru the carb. pull the drain plug in the bottom of the carb and measure the flow. I should fill a pint jar in 2 to 3 minutes. open fuel shut off valve two turns only. Had it been running OK before? When was the last time the air cleaner was serviced?

 

[powrguy]

I've got a new carb on the way, and I will be cleaning/servicing the air filter while I'm waiting.

I DO see that the governor linkage to the carb moves as the engine rpm changes slightly. It just seems to have NO throttle response at all, even though the throttle linkage opens the butterfly on the carb, but the engine remains at near-idle speed, regardless of throttle position, if that helps.

thanks

 

[powrguy]

Tractor had been running fine, 2 weeks ago, and when it was started this past weekend, the above situation occurred.

 

[Den N Ms]

Pwrguy,Save the original Marvel Shrebler caeb and have it rebuilt for later and you will need it someday. Royce on the N Ford board rebuilds carburetors and then tests them before sending them back to you,and he does GREAT work.Rebuild all your parts that you need,rather than replacing them.China parts are useless junk.
As R Geiger told you,Fuel flow to the carb means little, you need to check the flow thru the carb. pull the drain plug in the bottom of the carb and measure the flow. I should fill a pint jar in 2 minutes. open fuel shut off valve two turns only.
Unhook the air cleaner tube from the carb off try that and see if it helps.

 

[powrguy]

(quoted from post at 17:39:40 01/08/19) Pwrguy,Save the original Marvel Shrebler caeb and have it rebuilt for later and you will need it someday. Royce on the N Ford board rebuilds carburetors and then tests them before sending them back to you,and he does GREAT work.Rebuild all your parts that you need,rather than replacing them.China parts are useless junk.
As R Geiger told you,Fuel flow to the carb means little, you need to check the flow thru the carb. pull the drain plug in the bottom of the carb and measure the flow. I should fill a pint jar in 2 minutes. open fuel shut off valve two turns only.
Unhook the air cleaner tube from the carb off try that and see if it helps.

I found the email address for Royse, and I am gonna put the Chinese carb in, and get the old Marvel-Schebler rebuilt to reinstall it.

thanks

 

[powrguy]

OK, 8N Guru's, I put a new carb on, tried to start the tractor, and SOS; starts at idle and won't throttle up. I had COMPLETELY drained the fuel tank, put in fresh fuel, changed screen and gasket on the fuel tank shutoff bowl, removed air inlet pipe, cleaned air filter (wasn't sludged up at all, but changed the oil in it, anyway), cleaned and re-gapped plugs, etc.

Don't wanna pull the governor apart, as it was a SUDDEN problem, not a slow deterioration (like when the balls wear out).

Next move may be a bullet hole in the damned thing! LOL