1995 50 hp vro surging at half throttle

I'm stuck. Have a 50hp VRO Evinrude that surges at about 3000 to 3500 rpm (half throttle). It will start to cut out then pick back up, almost as if it is starved for fuel.

Took it to a local shop, had them rebuild the carbs, put in a new pick-up in the gas tank and new fuel line. Didn't help, so we replaced the VRO fuel pump. They said they put it in the water and ran it twice to test everything.

No difference.

There is a random chirp of the alarm. Thought it might be overheating, but it's pumping water just fine and can idle or run at 2000 rpm with no issues.

Check the oil tank cap for a plugged or stuck breather, it's seems ok.

Have spent close to $2,800 trying to get this figured out and I am reluctant to take it back to the shop for another big bill.

If I disengage the gears and give it WOT it will rev up just fine. It only surges under a load.

No point in revving it up in neutral.---Post your compression test numbers.---Always step #1 on an outboard.----Replace water pump impeller.

What is your full throttle RPM?
Revisit your sync&link.

Welcome to the Forum. When and how did the problem start? Had it been stored? Wish I had a box of all the VRO's that were thrown out, or replaced for nothing. I realize you might not be a mechanic, but a surging could be a number of things. My first question here should be answered. Has the spark been properly gap tested, plug colors noted, and new spark plugs? Be very careful throttling up with no load, (neutral)......major damage could result.

My vote is with RwButler on this one.... "Sync"!

Since you've had it looked at by at least one shop, I assume that they checked the compression, and the ignition system with the s/plugs removed in order to obtain the highest cranking speed... and all was well (Compression approx 100 and even on all four... Spark jumps a 7/16" gap at "all" throttle settings), and if so...........

The most common problem that causes the condition you describe is that the throttle linkage between the butterflies is not accurate... one slightly open/closed more-so than the other.

Right....Everytime a carb is removed it needs to be re-syncronized with it's partner/partners. Then they have to be set to advance at the correct motion of the timing. Your motor is done mechanically, so since there is plenty of play where the carbs bolt to the block, you must accomplish the aforementioned.....known as a link/sync....for short. What kind of shop did the repair work, was it a dealer? Did they mention that on the invoice?
My thoughts are, however, since you brought it into the shop with the surging problem....and the shop took $2800 of your hard earned "roofing" money......then the boat still ran the same as before.....ha!!! My guess is they didn't "cause" the problem, they just "missed" the problem. It happens alot....even with licensed dealers. That's why I only worked at a dealer for 12 weeks. Started my own business....can't work for anyone. I fix it....or die with it.

Your location ?----Help yourself and post the compression values on this 2 cylinder motor.------Does operation of the manual fuel pump help smooth it out when it starts surging ??

First took the boat in because it wouldn't run very well at idle and would keep stalling out. It has sat for 2 years.

The shop cleaned the tank, put new gas in it, and rebuilt the carbs. It's a factory authorized shop.

Took it out a few week later for the first time and it was surging. It was also leaking gas at the carbs.

Took it back and they said the bowl drain screws came loose and were sucking air. Said they were surprised it would even run. They said it was running fine, but didn't put it in the water.

I put it in the water a few days later and the same thing. Took a video of it and showed it to the shop.

They thought it might be a air leak in the fuel system. So they replaced the tank pickup and the hose to the motor.

They told me they put it in the water twice to see if it got better.

After the second time, they said it was the VRO fuel pump.

Had the VRO replaced but there was no improvement.

The shop is stumped and at a $150 an hour shop time for them to keep tinkering with it, I kinda feel I'm throwing good money after bad.

Thought of taking it to another shop, but in our area no one wants to work on older two strokes. I can understand why.

I'm in the East Bay near San Francisco.

Haven't done a compression test or checked the plugs. Would have thought the shop would have done it.

Also, when the carbs were rebuilt, they said the key switch was bad and they replaced it as well.

With how well the motor starts, will get up to about 2500 to 3000 rpms before cutting out, pumps water really well, does not smoke and I have run it for up to 45 minutes without it doing something really bad, I tend to think it's a sensor that is telling the motor it's either over heating or low on oil or something else.

Was thinking of disconnecting the VRO and oil, hooking up a separate tank with 50 to 1 gas and giving it a go.

Great shop, alright. You are a good and forgiving man. If they rebuilt carbs and "drain plugs" worked loose first time out...you should have "smelled the rat". I am so sorry for shops like that.....but they are not uncommon. I certainly wouldn't trust them, or ANY work they did. They should be taken to court. You need to get the carbs rebuilt then link/sync and ALL the work they did MUST be revisited by somebody competent. I appeal to my peers and mentors here for additional advice, my friend....I am so sorry.
If I had your boat here I'd fix it for free....after what you've been through. I have done lots of roofing in my life.....and every penny you earned is "hard earned". Sorry.....but I'm really pissed.

The drain plug can not suck air if loose !!

Sir Racer.....let's face it....they really took roofguy to the guillotine.

Roofguy.... A Factory authorized shop huh?

Carburetors are the easiest components of a outboard to repair and to repair correctly the first time!

A honest reliable shop would have honored you with warranty work... no charge to you... and for anyone calling themselves mechanics to charge $150 per hour and to return to you leaking carburetors... they would have to be graduates from Tobacco Road Elementary (A four grade dwelling), and that "Factory" that authorized them just has to be that broken down, splintered, wood shed on the outskirts of northern Siberia that's still featuring the Scott Atwater (sp) of the 1950's.

You'd be much better off to take that $150 you're shelling out every hour to those con artists and take all of them to Small Claims Court... Doubtful that you'd need a lawyer BUT keep in mind that the first consultation with a lawyer is free and his/her advice is well worth your time.

What's the name/location of that Jerkwater shop?

Ha! Shouldn't laugh.....but Joe, you have a way with words like nobody else. Roofguy has wounds to lick. Sounds like he started with some stale gas.....put his boat into the hands of idiots....now has to answer to his wife besides. The small claims should include distress and anxiety, besides total refund....with perhaps additional motor damages. I would love to be involved with assessment of what was damaged and unnecessarily replaced. If Roofguy can let us know the name of the shop, perhaps this Forum can save many others in the future.

Roofguy, what's that shops location ????

Boobie said:

Roofguy, what's that shops location ????

Click to expand...

I was also interested in their name Boobie... Gypsy Kicker Repairs?

Ha! He said East Bay, near San Francisco. He figures why shops don't work on older outboards for the wrong reason. They can't fix em?......No money in em? Well ..........East Bay shop knows how to make money off old outboards.

Yeah... Somehow that didn't occur to me Tim, that is, the "they can't fix em part". When I started out in the outboard trade repair line of 1960, all that existed was a magneto system and mechanical shift with the most technical setup being the electric starter. I don't remember if the generator setup existed with that V4 50hp of 1958/59 or not. Anyhow, every year since then, when OMC annually came out with something new, it was a breeze to learn it thoroughly. in essence, and reality, the marine mechanics of today, even the serious minded ones... I would think that a problem would exist in learning it all at one time. I guess that I was one of the lucky ones to start so early with OMC, and fortunate to get out of it in 1991. The assorted engines of today hanging on the transom of the few boats trailered thru my neighbor, their appearance (ugh) who designs those things?

Just like new vehicles today the new outboards are built from the inside out.----_When you stand on the " outside " you look at them and say ---" too many hose, wires and sensors.----Never designed for major repair work.----Buy a new one like every body else.

No new stuff for me, friends. I can try to fix em and usually succeed, but I recognize the thought process that goes into the engineering. It's a mad race to futility meet emissions yet create breathtaking performance, then hang an ugly skin on it and hope it lasts for 10 years without major failure. Brilliant, isn't it?

And to quote your closing Tim, of "Brilliant, isn't it?".........

I've replace the fuel pumps and one tank complete on my 1988 F150 as well as many other components (lost count)... and now the fuel pump of like design has failed on my late wifes' 1989 Crown Vic.

Incorporating a 12v electric pump inside of a gas tank!... Now that's Brilliant!

Also racerone, quoting your "Built from the inside out".... I've never thought of it like that, an exact description! The work (hours) I've had to go thru to replace a fallible $4.75 part! (sigh)

Right....tell you the truth. Heater core began leaking on our 1997 f 150. Of course NOBODY, works on my stuff but me. Called dealer for the "fun" of it. 8 hrs labor time...WHAT? Plus the $100 part.....gonna be $1000 bucks.....junk the truck, eh?
Drop steering column, remove dash, both upper and lower including air bag.....you know the story once you get to the firewall. Finally saw something that resembled an evaporator and heater housing.....nestled deep inside is the heater core....
Let me tell you how they constructed this vehicle.......they set a heater core on the table, then built a truck around it.
By the time I was done, the back of my hands were a bloody mess....but guess what? Only took me 6 1/2 hours....not counting bandaging time on hands, wrists and arms.

And since I think the "Roof-Guy" is taking a break, I'll continue on..... Heater core huh Tim?

1988 F-150...
Heater core replaced twice by yours truly. A few things to remove on the inside firewall, not too bad.

1989 Crown Vic...
Replaced once by a reliable shop, leaking again about 10 years later (10yrs ago). To remove, necessary to remove dash as explained by "racerone" . However, residing just outside Tampa Fl for the past 43 years (Temp 12/07/20=59 degrees-12noon) <-- I can live with that!... A "U" shaped length of copper pipe, the two heater hoses attached, yeah, that'll work! Might sell next Summer... AC= Perfect!

Wow! Beautiful vehicles. Let me know before you sell C-vic.....one way plane tickets are pretty cheap to Orlando.
Joe, you probably know that the old-fashioned green Prestone is way better than this "lifetime" pink crap. The Prestone in my 69 Chevy pickup is still perfect......last replaced in 1997.....only reason I had to change it out back then....was a late night rendezvous with a young moose on a lonely Ontario highway.