Evinrude 18HP 1960 low power

[salnaes]

My Evinrude 18HP Fastwin 1960 is totally re-built, and I’m performing break-in procedures. On the first run it was performing very well, but today it was no good. It sounds like it’s only working on one cylinder, and rpm is low on full throttle, and power is low. I discovered fuel leaking from the carburetor. It was wet on the outside. I have totally re-built the carb, and with complete new gaskets and all. Never the less there is fuel on the outside of the carb. Any thoughts?

[fleetwin]

Well, perhaps the inlet needle/float is stuck/defective.  Did you use OEM parts on the carb?  Many of the cheap parts are cheap for a reason.  Start the engine up, then unplug the fuel line….  If engine performance seems to come back before it runs out of fuel, then the carb is probably flooding over.

Nonetheless, you feel that the engine is running on one cylinder.  This could very well be the case as well.  Perhaps one of the reed valves has failed/got stuck open, which would explain the fuel being pushed back out of the carb.

[salnaes]

Thank you very much for your reply. I will perform the procedure you recommended to test the float/needle. It was a complete rep set I bought from China on Ebay, so you might be correct. I performed a complete overhaul of the carburetor. Float and needle are new.

[salnaes]

[fleetwin]

It is worth investing in the OEM carb kit, haven’t  heard anything good about that chinese stuff.

Let us know how you make out.  D

[lindy46]

Was gas running out front of the carb? Could be a stuck float or float hanging up somewhere. If the float isn’t closing the needle, gas will run out. When I rebuild a carb, I perform a “blow test” before re-installing it. With the carb upright, blow into the gas inlet. Air should flow through. Repeat procedure with carb upside down. No air should flow through.

[sutterhome]

DID THE BRASS NEEDLE SEAT FIT?

[fleetwin]

I thought I had re-responded to this post but perhaps not.   You mention that the engine sounds like it is running on just one cylinder and the power is low, along with fuel dripping/leaking from the carb.

Did you mess with the reed valves at all?  Change, rotate/flip them during the rebuild?  Perhaps one of the reed valves is broken/stuck open which would explain why it is running on one cylinder and pushing fuel out of the carb.

[salnaes]

I was lucky to purchase an OEM carb kit from a dealer here in Norway. I will try to switch float and needle soon. I might open to inspect the reed valves too.  Thanks for all advices.

[salnaes]

Well, the carb kit I bought now has wrong part number, so I have to go to the dealer and re-order the right one. Fleetwin. I did not mess with the reed valves. I performed a total rebuild of the 18 Horsepower from 1960, but I did not remove the reed valves from the plate where they are attached. They looked fine, so I just put on new gaskets on the plate and re-assembled the reed plate and manifold. See the image showing my reed plate with reeds mounted. They were never removed from the plate.

The kit I bought from a seller on ebay in China had part number 439071, which is the same number as the original OMC kit with float. But of course it is not an OMC product, so it might be bad quality.

I discovered that there was some fuel leakage from the fuel tube where it’s attached to the carb. That might be the reason why I experience fuel on the outside of the carb. I will fix this with a proper attachment. Could an improper attachment of the fuel tube causing leakage be the explanation of the bad performance from the outboard? May be it just did not get enough fuel to perform properly?

 

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