1989 Evinrude 75 HP - Running on One Cylinder? (Videos Included)

EDIT: Confirmed by part number E70ELCNB it's a "1982 70 HP"

Symptoms are as follows

• Idles fine at 800 RPMs however when put in gear the engine bogs out. To get it to not bog under light load I have to set the idle very high. The motor will then idle at 700-800 RPM in the tank but scream on muffs. If I do not adjust the idle very high it will run fine on muffs. This condition only presents in the water or tank.
  
  
• At WOT the engine is non responsive. It will very slowly climb to about 18 MPH.

During diagnostics I found the following. I'm unsure if this is right but I will be referring to the top cylinder as cylinder one, middle as cylinder two, bottom as cylinder three.

• Compression is fine. 110 - 120 PSI.
• All cylinders appear to "spit" fuel however cylinder one seems to do it the worst
• When covering cylinder one or three with a plastic bag there is little if any change. When covering cylinder two the engine immediately dies.
• When removing the spark plugs from cylinder one or three the motor runs the exact same. When removing from cylinder two the engine immediately dies.
• I put a spark plug tester inline with all three cylinders. I have spark. I shocked myself on cylinder three so I know for a fact I have spark.
• Pulled the plug on cylinder three and ran the motor. I really don't smell gas nor do I see gas\oil shooting out the hole. This is idle.
• The test tank is very oily after about ten minutes of runtime.
• Not sure if this is an issue but if you watch the last video at the 4 second mark you will notice water pouring out between the mid section and tail section. Otherwise it pisses fine.
• Some mechanic did supposedly rebuild the carbs. Before the carb rebuild I would completely die at WOT and could only idle. I did not run the boat for two years after the rebuild.

I appear to be running on one cylinder, what could be going on here. I'm thinking of moving the cabs around to see if the issue "follows" the carb.


Videos

- Boat-CarbGas - This video shows gas spitting out the carbs.

- Boat-CarbBag - This video shows me covering all carbs with a bag. Only covering the middle kills the engine.

- Boat-PullPlug - This video shows me pulling all plugs on the motor and observe no change. Pulling the middle kills the engine.

- Boat-2Plugs - This video shows the motor running with cylinder one and cylinder three's plug wires removed.

 

I did not run the boat for two years is your entire problem. The carbs got fouled up with gunk and need to be cleaned.

 

Thanks. I will disassemble, clean, and reassemble after seeing if my problem follows the carb. Keep it mind it did have ethanol free boat gas in it the entire time it sat. The last time it was run was at the shop and I never had the time to confirm his work. Other than this suspected problem it did fire right back up.

Are there any carb adjustments as in the carbs could have been put back together wrong? I'm looking at the manual and there doesn't seem to be for my year.

 

Gasoline sitting for 2 years in a carb bowl is subject to all environmental factors and in most cases will dry out and create a sticky varnish. The fuel will not smell right.

The most common issues that causes wet carbs is sticking float valves or gunked up mains.

You cannot blame the last guy here.

Once you get the bowls off; you can take a whiff and get a pretty good idea.

Boats stored in warm climates are more prone to problems, but so are boats store anywhere the sun may heat the case. Two summers is almost certainly enough time here in Minnesota to dry out the carbs to varnish.

The float valves and the mains are the likely issues, so it is a total carb cleaning for you. They’ll need to be soaked overnight in cleaner, not just a little spray either.

As for adjustments, about the only one you can try would be opening and closing the mains carefully a few times. You count the turns down to close first to closest quarter turn; or 1/8th. But this is fairly useless because the bowls are probably full of goo. So, just do the count and write it down for reference with all adjustment screws during the teardown.

 

Really appreciate the advice, I will be doing that this weekend and report back. Anything you recommend soaking the carbs in? For small engines I've always used pine sol believe it or not in a Harbor Freight ultrasonic cleaner.

I can not find the number of "turns" anywhere in the manual, do you happen to know? I know the procedure to set the screw until it sits and count the number of turns but given I did not personally take the carbs apart last time I can't be sure it's correct.

If I ever plan on storing the boat for 2 years again what's the best way? Just run it completely dry.

 

Hi, I second fallguy's diagnosis, old fuel sitting in systems is a common issue in all motors, and with carbies and their many little galleries, orifices, and jets it is like varnish, and smells like turpentine, or worse. Your rubber fuel lines may also be lined with gunk, and stiff or brittle. I have had them crumble in my hands. It also sits in tanks and gunks up fuel pumps, so after your cleaning of carbs, more gunk dislodges from the fuel tank, the pump, the filters, and hoses, and you start all over again. Modern fuel isn't like what we had in the 70's and 80's; now it's a time bomb for the unwary. Start with your fuel tank, and when it's clean replace or thoroughly clean your lines, clean your pump, it can harbor globs of muck, then clean or replace the pressure lines. Then look at the carbies. Next time pour some fuel conditioner in the tank, and run it for about 10 minutes so it reaches the carbs, then you can put it in storage; but start and run a few minutes to warm up every few months to re-oil internal components and prevent oil seal lips sticking and becoming damaged. There are carby cleaner solutions and sprays that work well, wear eye protection and gloves, in a ventilated area, it's nasty stuff. Also do a regular service - oils, filters, etc. before your trip. Be patient, do a thorough job, and you will benefit. Good luck.

 

Thanks for the advice it totally makes sense. I'll be pulling. Any recommended carb soak cleaner? As I said above I've always used pine sol and an ultrasonic in the past.

Out of curiosity why would gummed up carbs cause the pooling\spitting that was observed in the "Boat-CarbsGas" video. If it was clogged\plugged wouldn't you expect no fuel at all?

 

Ask a local mechanic what works well, I'm in Australia so prob have different brands here. Spray cans with a tube are helpful in carbies, and non pressurised bigger containers are much better value. Stuff with lots of ether is good, if you stay away from heat sources, and don't smoke. If the float needle valves or floats are sticky they can be held open, flooding the carby with fuel coming out of overflow lines and anywhere else it can escape, while the pump just keeps on pumping. The ultrasonic bath is great for the carbies, and the stripped down pump if it is mechanical. You may need pipe cleaners, compressed air, old tooth brushes, thin bits of wire, clean rags, magnifying glasses, and several other items to clean out your parts, and don't mix your carby components. If the adjustable carby screw is on the atmosphere side it is an air bleed valve, and if it is on the engine side it is an enrichener valve, and all 3 carbs may run best at slightly different settings, generally somewhere between 1 turn out from closed, and 3 turns out, not exactly sure for your engine. Post the exact make, year, and model on here and someone may have a manual to tell you, or look it up on the interweb.
Don't bother moving the carbs about, just clean them properly again. After a couple years sitting in one spot, your water pump may need a new impeller too.
Compression is only just fine - under 100 PSI and it is a shagged motor usually. Might be time to think about upgrading instead of blowing money on an old motor.

 

Count the turns to close for each screw before removing them. For 3 carbs, it is unlikely they will vary. The expection is that all 3 carbs will have all adjustments set similarly.

Running the engine periodically is the only sure way to keep it in running condition. Running it ‘dry’ means it will probably still have some residues in the carbs, and my experience is those residues go to varnish quicker.

I’ve experience the gamut of trying to deal with finicky carbs and the only sure way is to run the engine with earmuffs now and then. I’d try for about 90 days. My 2.5hp Yamaha has a tiny carb and it gets gunked up in about 120 days. Your carb jets are bigger and might tolerate a longer period, but carbs need fuel to go through and not sit.

Fuel stabilizer can help, but is no panacea.

 

There are many actual carb cleaners on the market
Gunk make one and the other which we have used quite a bit (ages ago) was called just that Carb Cleaner
The can was big enough to immerse and clean 1100 Holley double pumpers.
I think that it was quite caustic so pay heed to the Haz/Whmis information. Gloves, mask etc. Note wrt masks. People often think that a particulate mask qualifies. There are specific masks with various mediums for various vapors. Back in the day, we never paid attention. Using the carb cleaner in an open area would probably suffice.
Then you can buy for little money, orfice cleaners which are like the ones that you use to say clean the tips of an acetylene torch, mig tip etc but much longer. This will ensure that
all of the pressure balancing paths in the carb are clear. If you cannot find orfice cleaners, you can strip back various guages of automotive copper wire and pull off some strands to make
a "make do" cleaner

I cannot see Pinesol having the same cleaning qualities as dedicated carb cleaners

I am referring to the gallon size of cleaner or 2 quart size cans, not the spray cleaner. You want to immerse the entire carb in the liquid for several hours per the instructions

 

Yeah, forget the Pine Sol.

The reason the carbs are wet is they are not able to flow properly and mix air and fuel and so all you get is some gas flowing because it cannot vaporize properly.

Wet carbs are a good indicator of fouled passages.

 

Thanks for the advice everyone. I am doing my top carb now. I do think this is carb related as I shot some butane into the open port and got the motor to kick up a bit.

One thing I noticed when i was taking everything apart was that all screws were slammed shut. There was no close 1.5 turns on any of them. Not sure if this is normal. The carb is 326929.

 

Slammed shut? No.

Show us the bottom and the bowls. Make sure you pull the main needle..

I don’t know that carb personally.

@C. Dog may have touched these

 

Bowl was super super clean. Needle had a little bit of black varnish at the tip. Either way I'm doing a full dip with Berryman carb dip and carb cleaner

All those screws depicted on the attached images were completely bottomed out. I'm not sure if this matches the middle carb as I don't want to "mess" with that one yet

 

The main needle can’t be bottomed out.