# 70 HP Evinrude falls on its face



## Slipfloat10 (Oct 27, 2018)

My 1993 70 HP Evinrude, on a 17' Lowe aluminum, runs great on plane for about 5 minutes, then just falls on its face and dies. I can immediately restart the engine, and bring it back on plane, after idling for a few minutes, but it repeats the fall on face thing. It seems to me that I'm running out of fuel, and the fuel filter appears to be original, so I've ordered a new filter, which should be in today. I'll replace the fuel filter when it arrives, and I'll head to the lake Tuesday to see if this fixes the problem, but I just wanted to test the waters to see if anyone else has any ideas. I recently purchased the boat from a man who claims to have had the carbs cleaned last Spring; I'm inclined to believe him because this doesn't seem to be a carb issue. Possibly low fuel pump output, but they're proud of those little suckers, so I wanted to exhaust other options first. BTW, the primer bulb is still firm when the engine dies.
Thanks in advance.
Ron


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## CedarRiverScooter (Oct 27, 2018)

I've heard that when you think it's fuel, the prob is actually spark & vice versa.

You could check spark on all cyls when it acts up.

Maybe a coil pack loses power when hot.


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## Pappy (Oct 27, 2018)

Let's try a few simpler things before diving into spark. 
The primer bulb should not be firm at all no matter what RPM the engine runs at. The bulb is on the suction side of the pump when the engine is running so will never be firm. 
Now.....When the engine exhibits this issue have someone pump the primer bulb and see if the engine regains and maintains RPM. That will tell you if you have a fuel pump issue. 
Start there. 
Look for any kinked fuel delivery lines from the tank to the engine as well. 
Third item. If you have the silver colored fuel line, get rid of it. That line comes apart internally and will create a fuel restriction. Do a search on here and you will see the photos of this.


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## GYPSY400 (Oct 28, 2018)

Pappy said:


> Let's try a few simpler things before diving into spark.
> The primer bulb should not be firm at all no matter what RPM the engine runs at. The bulb is on the suction side of the pump when the engine is running so will never be firm.
> Now.....When the engine exhibits this issue have someone pump the primer bulb and see if the engine regains and maintains RPM. That will tell you if you have a fuel pump issue.
> Start there.
> ...


^^^ this^^^
Plus I have a feeling the float level is not correct or the needle valve is restricted. Sounds like the bowl is running dry inn the carb.

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## Pappy (Oct 28, 2018)

If the float were set incorrectly why would the engine run normally at high power for around 5 minutes? 
Same for the restricted needle valve..... 
Both would have immediate responses.


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## GYPSY400 (Oct 29, 2018)

Pappy said:


> If the float were set incorrectly why would the engine run normally at high power for around 5 minutes?
> Same for the restricted needle valve.....
> Both would have immediate responses.


My theory is this.. the float bowl fills slowly ( or not enough), enough to allow idle. Once under a high fuel demand the bowl drains faster than it can fill. This may take a few minutes as it's probably a triple carb engine.
Once again, just a theory. 

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## Pappy (Oct 29, 2018)

So you would have a fellow dive into his carbs based on a theory, on an engine that you are not even sure about the number of carburetors on. 
We may get to this but the simple things can and should be checked and checked off prior to just tearing things apart based on a theory. 
Sit back, read and learn as this goes, if the OP comes back and starts the process that is.....


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## GYPSY400 (Oct 29, 2018)

Pappy said:


> So you would have a fellow dive into his carbs based on a theory, on an engine that you are not even sure about the number of carburetors on.
> We may get to this but the simple things can and should be checked and checked off prior to just tearing things apart based on a theory.
> Sit back, read and learn as this goes, if the OP comes back and starts the process that is.....


Your reading me all wrong.
I agreed with your previous post as a first step, naturally I would examine the cheapest and simplist things first.
Then I would examine the float bowl "theory" as the OP said the previous owner has cleaned the carbs, but did something get missed or misadjusted - who knows? (BTW I confirmed 3 carbs)

We also don't know if this is a spark loss issue or possibly a VRO issue, which as you know is a whole different ball game. It's hard for us keyboard cowboys to troubleshoot something without seeing and hearing what the symptoms are.


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## Pappy (Oct 30, 2018)

Ya' know.....You're right. I think I will sit back and just let you take over and learn instead......


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## GYPSY400 (Oct 30, 2018)

Pappy said:


> Ya' know.....You're right. I think I will sit back and just let you take over and learn instead......


I'm NOT trying to take over.. 

I've learned a few things from you in the past, and I respect your knowledge and experience.

I was merely putting my 2 cents in so the OP can try more than one thing at a time before checking back in. 
If you think my " theory " is wrong, then please educate me (and the rest of us) on why and how it is.

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## WALI4VR (Nov 1, 2018)

Pappy said:


> Let's try a few simpler things before diving into spark.
> The primer bulb should not be firm at all no matter what RPM the engine runs at. The bulb is on the suction side of the pump when the engine is running so will never be firm.
> Now.....When the engine exhibits this issue have someone pump the primer bulb and see if the engine regains and maintains RPM. That will tell you if you have a fuel pump issue.
> Start there.
> ...


For whatever it's worth...
I've had 3 friends with those 3 cylinder motors have almost exactly the same mistake. After many hours of checking this, that, and every other thing we could think of I called on an old friend, outboard motor technician. I hope your problem isn't what all 3 friends had.
With engine warmed up and idling, try spraying some carb cleaner along the seam where the two halves of the block mate together. If the motor speeds up the mating surface is no longer sealed. It means a complete disassembly of the engine to repair it. My first friend junked his and repowered the boat, the second guy sold his unit for cheap, and the third because of his background as an auto tech bought a Johnson repair manual and repaired his himself. Best of luck and I hope your problem is not the same as theirs was. 

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## handyandy (Nov 2, 2018)

WALI4VR said:


> Pappy said:
> 
> 
> > Let's try a few simpler things before diving into spark.
> ...



Man if you have any other friends that ever want to almost give away a omc 3 cyl let me know, one of my favorite engines. To the op try what pappy said first easiest thing to do and check, it sounds like primer bulb to me or fuel pump getting weak. If it ends up being a pump spend the extra and get a USA made one. The cheap china diaphragm pumps never seem to last all that long, the rubber gets brittle a lot sooner than the better ones. Another thing I've seen before is a lot of the newer fuel line primer bulb combos the newer low vapor line I've seen the inner layer of the hose separate from the outer layer. When this happens sometimes at idle or lower rpm the line stays open enough to run, but when you open it up enough suction pulls the inner lining of the hose in restricting the fuel flow. If it does end up being your bulb or fuel line get a quality bulb like a new evinrude brp one that's what I'm running now it has lasted longer than any of the cheapy ones at wal mart or where ever I'm sure the mercury or yamaha ones are good too, this is just what I chose to run cause a buddy of mine had one that lasted him a long time.

https://www.amazon.com/BRP-5008586-Primer-Bulb-Kit/dp/B0058K3IG0 

Also run good fuel hose, I tend to do enough work on boat engines, car engines, and small engines/equipment that I just keep spools of common hose sizes. I have this hose it has been pretty good so far in everything I've used it on from my boat to tractors, mowers, and some auto applications. Once again on the line just make sure you get some good usa made line napa tends to carry decent fuel hose if you just end up needing a couple feet. I like having crap on hand to avoid wasting time making a bunch of part store runs so I have this.

https://www.ebay.com/itm/FUEL-HOSE-HI-TEMP-3-ROLLS-ASSORTED-SIZES-1-4-5-16-3-8-R7-MADE-IN-USA-E-85/401497968992?epid=1761031813&hash=item5d7b24d160:gUQAAOSwFm5a5HsQ:rk:45f:0


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## Slipfloat10 (Nov 2, 2018)

I want to thank everyone for all of the great info and suggestions. 
When I bought the boat it had 3/4 tank of fuel, and I don't know how long it had been in the boat. The guy I bought it from told me had taken the boat out the previous week, that it ran great, but I'm skeptical about those claims. The fuel filter appeared to be OE, so I started by replacing that, so I'll take her out next week and see how it runs. I'll let you guys know.
Thanks again,
Ron


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## richg99 (Nov 4, 2018)

You've already received a lot of good advice. So, I'll only share my personal experience with a '96 Johnson. Ran good, ran bad. Never found anything consistent, but it wasn't right.

What had changed??? My gasoline had changed. It was now the EPA approved Ethanol crap. Turns out that the Ethanol blended gasoline rotted the inside of the fuel line, and maybe the bulb, too. Oh, it also cleaned out the old tank, too. Of course, all of that crap found its way into my system while we were at it.

As soon as I replaced the line and bulb, she ran well.
rich


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## turbotodd (Nov 15, 2018)

Had a 70 on our old Rhyancraft 17 footer.

Same exact complaint and issue. That's how I bought it-cheap-because the PO couldn't figure it out.

Timing was not advancing properly. Repaired the linkages, problem solved. Kept it about 6 months or so, dumped it in the spring. Good boat and good motor, just wasn't what I wanted.


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## sunshine (Nov 15, 2018)

Had the same issue on a bass boat, it ended up being the liner in the fuel line had separated from the hose and was collapsing when running WOT. New fuel lines and back to action.


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