40 HP Evinrude twin runs like doo-doo

[halmc]

Mid eighties (guess) two stroke 40 hp Evinrude twin: Gorgeous blue spark at both plugs; 150# compression on both cylinders; Carbs clean as a whistle; Starts very weak, runs weak on one cylinder, occasionally hits very momentarily on the other. More than one set of new plugs tried w/o any change in symptoms. Fuel hose bulb pumped w/no change in symptoms. Momentarily actuating the primer from the control head (where the throttle/gearshift/ingition key is) produces just a bit stronger running. Removing the 'running' plug shows a plug fairly drenched with gasoline.

Any suggestions?

Another question: the fuel hose on the engine side of the connection to the engine runs back along the left side of the engine to some sort of a massive hunk of I don't know what. What is it? I see that there is a relatively small solenoid on the right side of the engine with a red sort of toggle switch on the side that is infact the 'primer' that permits the engine to suck in raw gasoline just at the very top of the intake on the carburetor, well down stream of the venturi. What's the correct position for the switch?

Thanks, Harold in Tallahassee, FL PS: I can gather up the model and serial number of the engine tomorrow if needs be.

PPS: what are the symptoms of a failed reed valve?

PPPS: are there electrical schematics anywhere on the 'net for this sort of engine?

TIA!!!

 

[5150abf]

Re: 40 HP Evinrude twin runs like doo-doo

1st things first, yes, get the serial number and model number and if you don't have one go to the iboats store and order a manual as soon as you find out what you have,it will save you a hundred times the price in frustration and buying the wrong parts.
You are in the right place, the guys here are very good at what they do.
So start with the model and serial number.

 

[HighTrim]

Re: 40 HP Evinrude twin runs like doo-doo

The normal operating position is to have that red lever positioned over top of the solenoid and aimed at the other end of the solenoid. Look upon the primer solenoid as an electric choke. TD has a pic of this.

What is the condition of the plug from the faulty cylinder?

Did you rebuild the carbs during cleaning? Were the jets/orifices removed and properly cleaned? That would be my guess as to where your trouble is. You will need a special tool like the following to remove them. Pic compliments of FR.



You should get yourself a factory OEM manual, it will pay for itself a million times over. Check ebay, or www.outboardbooks.com for a factory reprint.

 

[halmc]

Re: 40 HP Evinrude twin runs like doo-doo

The normal operating position is to have that red lever positioned over top of the solenoid and aimed at the other end of the solenoid. Look upon the primer solenoid as an electric choke. TD has a pic of this.

Yeah, the primer is an enrichening device much like a choke but its mechanical operation is quite different. Anyhow, the red lever is quite near one end of the solenoid. Your saying that the longer end of the red lever should point to the more distant end of the solenoid, correct? Don't know what TD is.

What is the condition of the plug from the faulty cylinder?

Sorry I should have mentioned that: both are bathed in raw fuel. In fact so much fuel is in the exhaust that I am concerned both about the enviroment and, more immediately, fire.

Did you rebuild the carbs during cleaning? Were the jets/orifices removed and properly cleaned?

Yes. Both carbs were "boiled" in automotive carb cleaner with all removable jets removed. I have a complete set of special jet removing tools from years of working on motorcycles and other engines with carburetors. There was precious little residue in any part of the carbs -- essentially none. I did it because the carbs are easy to get to and I wanted to eliminate that as a possible cause. I have also swapped the top carb with the bottom: as before the top cylinder makes power and the bottom doesn't.

That would be my guess as to where your trouble is.

Seems to me that clogged jets wouldn't bathe plugs (and exhaust, btw) in raw fuel.

You should get yourself a factory OEM manual, it will pay for itself a million times over.

Normally I'd accept that as excellent advice, but this engine is not mine -- it's the property of a marina neighbor who has had half the hamfisted "mechanics" in our town take a drive out to to a lake fix it -- all w/o success. I'm gonna fix the cussed thing long before the manual would arrive; in fact, this w/e I'm gonna drag the boat out of the water and take it to my shop ashore. I'm looking to jump start the process. There doesn't appear to be any mechanical damage to the powerhead; it has spark, fuel and compression. Normally that will get a fellow some noise, but one cylinder is weak and the other kaput. weird.

Would you consider my question re a broken reed? It's been quite a few years since I even considered a reed valved engine, and sure appears this old engnie has 'em(?)

 

[HighTrim]

Re: 40 HP Evinrude twin runs like doo-doo

Here is a pic of the primer solenoids running postion, compliments of TD



If it is in fact the opposite way, that would explain your 'flooding' since it allows fuel to flow through it to the crankcase area. This would be in the instance that the battery dies and you need to rope start it. I just said to look at it like a choke to simplify things.

I mentioned the jets since getting response from choking/enrichening it is usually a symptom of clogged jets.

Also, what plugs are you running?

 

[Jacob645]

Re: 40 HP Evinrude twin runs like doo-doo

How do your coils look? Any cracks?

 

[halmc]

Re: 40 HP Evinrude twin runs like doo-doo

Here is a pic of the primer solenoids running postion, compliments of TD

Thanks, that's very helpful.

If it is in fact the opposite way, that would explain your 'flooding' since it allows fuel to flow through it to the crankcase area. This would be in the instance that the battery dies and you need to rope start it. I just said to look at it like a choke to simplify things.

Yup, understand. But I don't think the lever is the issue, since I have tried the engine with the lever in several positions, including the one in the attachment. However, it is good to know where it belongs.

I mentioned the jets since getting response from choking/enrichening it is usually a symptom of clogged jets.

Agreed, if its running in a lean condition, the primer should make it run better. The engine runs only slightly -- and inexplicably -- better with the electric primer on. And the missing cylinder doesn't fire at all, primer on or off. And there's enough fuel about to make me keep an eye on a fire extinguiser as I hang my butt off the "stern" of this pontoon boat. A miserable position from which to troubleshoot.

Also, what plugs are you running?

Ive tried two types: NGK BUHW's and just for grins, autolite 4316's, a plug with a more conventional electrode configuration, but a cold cold plug nonetheless. I use the latter in two stroke motorcycles. A change in plugs, old to new; NGK to Autolite yields no change in symptoms.

How do your coils look? Any cracks?

They don't look abmormal in any way. No cracks. And there is that big fat blue spark -- at least when the plugs are laying comfortable outside the engine.

This may be my year for weird stuff. Last month I bought a 1999 'as is where is' Jeep Wrangler from a used car lot. As I drove the Jeep, it slowly overheated. Bring it back down to an idle, and the heat would bleed off, to normal operating temperature. The faster I drove, the hotter it got. After trying every thing I could think of, inlcuding a fine new three core radiator and differential compression check, (and in fact, during that very check) I noticed that the mechanical fan on the engine was blowing air toward the front of the car. Some DPO (distinguished prior owner) had installed the wrong fan. With NO fan the Jeep runs sixty F. degrees cooler. That was a first for me, and perhaps prepared me for whatever the issue is with this old outboard!

What's all that stuff at the left rear of the engine that seems associated with the fuel hose?? Not the fuel pump: it's at the front. The stuff I'm taling about is at the rear. I'll post an attachment if I visit the boat today, which I probably will.

The eyes of the marina are upon me.

 

[tashasdaddy]

Re: 40 HP Evinrude twin runs like doo-doo

get the model #'s, also a pic of the fuel stuff your talking about.

the jeep it sound like the fan was wired backwards. it is a dc motor.

 

[Faztbullet]

Re: 40 HP Evinrude twin runs like doo-doo

Please post model #. There was a late 80,s early 90's year that the carbs was just junk on 40/50's!! The are identified as having a adjustable air idle (surrounded by brass barrel) and balance tube hose. Most of the problems were idle and mid range due to flooding. I rebuilt a set 3 times and no fix. OMC rep told me to file 13 them and install a set off a 86-88 model. Was told this was common problem with these.

 

[halmc]

Re: 40 HP Evinrude twin runs like doo-doo

get the model #'s, also a pic of the fuel stuff your talking about.

the jeep it sound like the fan was wired backwards. it is a dc motor.

I'll get both the model number and the pic of the fuel stuff. The Jeep has a mechanical fan which, like alternator, AC, PS, is driven off the crankshaft by a serpentine belt. It left the factory with a CCW blade, arrived in my hands with a CW blade.

OMC rep told me to file 13 them and install a set off a 86-88 model. Was told this was common problem with these.

Wouldn't that be just my luck. No balance tube on these puppies, but I'll get the model number today, and thanks to all.

 

[halmc]

Re: 40 HP Evinrude twin runs like doo-doo

Please post model #.

Model number is: E40TLCCS

also a pic of the fuel stuff your talking about

Well, after very careful examination, evaluation and analysis of that "fuel" stuff I find that it is chuck full of wires; thus I've formed a working hypothesis that it is in fact "electrical" stuff.:redface:

 

[HighTrim]

Re: 40 HP Evinrude twin runs like doo-doo

Just for your info, you should be running Champion QL77JC4 gapped to .030

They are what the motor was designed to run on and are reccomended.

 

[halmc]

Re: 40 HP Evinrude twin runs like doo-doo

Just for your info, you should be running Champion QL77JC4 gapped to .030

They are what the motor was designed to run on and are reccomended.

I don't think my issue is caused by plugs, but it can't hurt to have the right ones. Thanks! What year does the engine turn out to be?

 

[HighTrim]

Re: 40 HP Evinrude twin runs like doo-doo

1988