87 70hp evinrude lacks power

[Rocketman 1]

I have 87 evinrude model e70tlcu that lacks power. It bogs at wide open throttle and I have to back off a bit unless i push the choke. which then it goes like a bat out of hell. bogs, bat out of hell, bogs, etc... as I push the choke which tells me it's lacking fuel. Fuel filter is clean, fresh gas. What might be causing this? Thanks

 

[flyingfinn73]

Re: 87 70hp evinrude lacks power

i'm not an outboard specific expert, but done enuf work on 2 strokes to guess it sounds like maybe a gummed up main jet. i would start with cleaning up the carb(s) if choking it gets it past your bog point. just my opinion

 

[Rocketman 1]

Re: 87 70hp evinrude lacks power

Well I'm actually pushing the primer solenoid. Not an actual choke I guess. When you squeeze the primer bulb while engine is at high speed it kind of seems to help but not significantly like using the primer soleniod. I have already rebuilt all 3 carbs.

 

[flyingfinn73]

Re: 87 70hp evinrude lacks power

hmm. not sure. i would still guess trouble is somewhere in carbs. squeezing the primer bulb will only pressurize the line as far as the vro unit, which would only help if there was a leakdown somewhere between the bulb and vro. but pushing in the primer button sends some of the output from the vro directly into the intake manifold bypassing the carbs which seems to be what you are finding helps cure the lack of fuel from the carbs.

 

[Rocketman 1]

Re: 87 70hp evinrude lacks power

Possible, but what in the carbs? Not much to em. Idle air orifice. High speed orifice and the float needle and seat. All clean. All new. All correct oem parts. The floats are set to specs. The top float might be set a slight on the lean side but i'm not talking much. Could it possibly be the fuel pump side of the vro can't deliver enough fuel? Requiring a rebuild of it? I see the kit is 135.00. Expensive for what it is.

thanks

steve

 

[Rocketman 1]

Re: 87 70hp evinrude lacks power

If it was a faulty fuel pump would squeezing the bulb allow fuel to be forced past the pump? When I squeezed the bulb I didn't notice a huge difference in performance.

 

[flyingfinn73]

Re: 87 70hp evinrude lacks power

sorry not more help to you. all i can say for sure is that the primer solenoid also gets it's fuel via the vro so if that was faulty i would think that pushing the button for that wouldn't result in any difference in your wot situation. squeezing the primer bulb would increase pressure TO the vro, but dont know if it would actually "pressure through" the vro and into your carbs. one thing to keep in mind with 2 strokes, is a bog can be caused by either a too rich, or a too lean condition, but in your case seems to be the lean side, which can be very dangerous if you push it that far on the lean side. good luck

 

[Rocketman 1]

Re: 87 70hp evinrude lacks power

Thanks for the reply back. You are a great help. I realize that power head damage is possible with lean mixture but not sure how else to test it after making adjustments other than WOT. I try and keep it to a minimum. Would mixing oil in the gas help. That was my thought till I get this figured out.

I'm going to test the anti siphon valve and check to make sure gas lines are clear. What's weird is that I didn't have this problem last fall before storage. I had problems last year with it running to rich and stalling when just placed in gear under load. That's when I rebuilt the carbs and reed plates with all new gaskets. To no avail. It had power like you wouldn't believe when you punched it and at WOT. But seemed to flood out under load at low rpm's. But it would idle all day long. This spring I tested a faulty stator and replaced. Timed motor, and did a lync and sync. on carbs. When I took it on the water for a test run it idled great, and would have run all day in gear under load at low rpm's but it was a gutless wonder starving for fuel. Extremely odd to me. That's why I don't think it is the pump either but my dad is kind of stuck on that idea. I also replaced the fuel gauge sender so I'm thinking maybe a piece of crap got stuck in the line somewhere. Just a guess. Would you have any suggestion where else to look or test. I have had the top carb off this spring already so I know that's clean but i'm also thinking about popping off the other two just to rule them out.

thanks for your time

Steve

 

[patrick4266]

Re: 87 70hp evinrude lacks power

Same thing happened to me on a 83-70hp motor. Did the same things you did,carb rebuild, link sync ect, still bogged down. Turns out one of the welch plugs I had replaced fell out.

 

[Rocketman 1]

Re: 87 70hp evinrude lacks power

I finally got a chance to run some tests. I was doing the flow chart test of the vro. trying to rule that out. just have a couple questions.

Here is the link
http://www.maxrules.com/graphics/VROpics/VROflowchart.jpg

I will follow the chart:

Pump holds pressure
Rapidly removed pressure while covering fuel outlet - wait 5 sec. uncover outlet - pump clicked
Applied 15 in. hg. vaccum, covered fuel outlet, rapidly removed vaccum, waited 5 sec, uncoverd fuel outlet. Pumped clicked BUT it was not a sharp click like the other ones. It was more of a muffled springy sounding click. Is that normal or o.k.

Also when I do the first test on the flow chart the pump clicks about every other pump of the tester. About 3 to five times up to the 15 lbs of pressure. It only clicks once every time though. Is this Normal???
Thanks for your help in advance.

Steve

 

[rogerwa]

Re: 87 70hp evinrude lacks power

One easy thing to check is float height.. Set too low and you may be starving for fuel.

 

[Rocketman 1]

Re: 87 70hp evinrude lacks power

Think I may have found the problem. Before I had the problem of starving for fuel at WOT I had checked top carb float height. Over the last two weeks I've been thinking about what could be wrong with the carbs. WHEN IT HIT ME!! I can;t remember reinstalling the nozzle gasket between the float chamber and the carb assembly. When I took it apart to check it - it was missing. I will let you know for sure when I get the parts. Thanks for everyone making me think about the carbs.

 

[Rocketman 1]

Re: 87 70hp evinrude lacks power

FOLLOW UP - Runs like a dream. It was one stinking little nozzle gasket in the #1 carb. Thanks for all the help