1979 Evinrude 15 (15904e) saga continues..

[billybuck1]

Still having choke problems...compression good (per mechanic), replaced a power pack. Motor runs great (on mufflers) and idles smoothly, but will not start when cold. Choke plate closes well, but she isn't drawing fuel. I pulled and dismantled the carb yesterday (just rebuilt with kit weeks ago), very clean, no obstruction in the high speed jet. Carb to intake gasket in good shape as is carb to bowl. Reassembled, reinstalled, still would not start....until I stuffed a shop towel in the carb throat, then voooom! Where can I be losing vacum and how can I find it?

I'm thinking of installing bolts to block the two small holes in the choke plate. I don't know what long term consequences this will bring, but I'm out of ideas. Maybe I'll check compression for kicks, even though mechanic said he did. This engine was rebuilt around 8 years ago and might have 10 hours on it since.

Any thoughts on impact of blocking the two small choke plate holes?

 

[Cofe]

Re: 1979 Evinrude 15 (15904e) saga continues..

After reading your post, the first thing that comes to mind is to replace all fuel lines, even the bulb and hose.
Make sure to use the plastic ties that are designed for outboard motors. "they have a rounded clamp so air won't get in on the fitting." Or a suitable hose clamp........ Air can get into the fuel system and create your described problems.
I once found the upper portion of the gas tank suction tube inside the gas tank, was leaking air into the system.

 

[Daviet]

Re: 1979 Evinrude 15 (15904e) saga continues..

I don't think putting screws in the choke plate will fix your problem.
Does the primer bulb pump up firm?
Is the float level set to proper depth?
How is the spark,will it jump a 7/16" gap and is it bright blue?
Recheck your compression, and do you have the correct spark plugs installed?

 

[billybuck1]

Re: 1979 Evinrude 15 (15904e) saga continues..

I just did replace both fuel lines under the cowl when I replaced the fuel pump. The bulb does pump up firm. When I got home tonight, I placed a piece of duct tape over the two small holes in the butterfly plate and pumped the bulb to firm. She fired on the first pull choked, then unchoked her and she started and ran perfectly two pulls later. I'll do this a few more days, if this continues, JB Weld is going in those holes. The engine does have the correct plugs. I havn't checked spark since she runs great once she gets fuel. The float is new. I did not fool with the tang when installed but lack of fuel seems only an issue at start up.

 

[the machinist]

Re: 1979 Evinrude 15 (15904e) saga continues..

It might be a long shot, but your crankshaft seals could be not sealing good enough to give you enough vacuum inside the engine & not able to pull the fuel in thru the carburetor.

The upper is fairly easy to replace, but the lower one has to have the powerhead removed.

 

[jmendoza]

Re: 1979 Evinrude 15 (15904e) saga continues..

I agree, you probably have poor crankcase compression, which will make it not pull fuel from the carb very well when starting. Things to check are the carb to intake manifold gasket, manifold gasket, reeds, top and bottom crankshaft seals, and the crankcase cover to block sealing surfaces(metal to metal).

The problem I have with my 1975 9.9/15 is that it chokes too well; I have to be lightning quick to push the choke off before the engine floods once it fires. So you have another problem, and it;'s not those two holes in the choke plate. Poor crankcase compression will eventually cause a lean condition and possible engine failure.

 

[boobie]

Re: 1979 Evinrude 15 (15904e) saga continues..

Have you ever done a good de-carb on this mtr ? If the bottom rings are stuck you can still have good compression but no "suck" to bring in the fuel/air mix. Just a thought.

 

[billybuck1]

Re: 1979 Evinrude 15 (15904e) saga continues..

I've reposted this issue several times so it wouldn't get stale. I did not repeat everything, including that this engine was rebuilt less than 10 operating hours ago, though that was 8 years ago. Wouldn't the crank seals have been replaced during the rebuild? I guess that isn't certain but isn't it likely?

She started right up again tonight with the tape over the choke plate holes.

I'm wondering if Daviet's comment about the float might make the most sense. Maybe the fuel in the bowl is just a bit low which might reduce the head pressure up the jet just enough that the choke won't pull a sufficient quantity to start her. Thoughts?

 

[Daviet]

Re: 1979 Evinrude 15 (15904e) saga continues..

Seals can go bad when sitting, the oil in the fuel helps keep seals plyable, sitting for eight years could cause a seals to give you problems.

 

[boobie]

Re: 1979 Evinrude 15 (15904e) saga continues..

Sitting for 8 yrs could also cause rings to stick if it wasn't put away properly.