1977 Evinrude 55hp Bogs at WOT.

[Wetwilly62]

Working on 55hp 1977 Evinrude, starts and idles great. Bogs down at wot. Compression 158 /164. New fuel lines and pump. Plugs gapped at 0.40. Sparks jumps 7/16 gap. Seems ok until about 1200 rpm then Boggs max rpm about 1800. Leaf plares look good. Carbs have been gone through twice. Have had the trigger and all other electrical components tested. Link and sync good. Read on another post about these loopers and this issue Help please.

 

[oldboat1]

Try a .030 plug gap.

 

[Wetwilly62]

Will do. Thanks its giving me a fit. Went back into carbs found inner float bowl seal on one carb cut , and the other doesn't show signs of being compressed. oldboat1 Would this affect it ?

 

[racerone]

Yes it would.----Fuel in the carburetor needs atmospheric pressure on it.

 

[oldboat1]

Could. Try regapping first.

 

[Wetwilly62]

racerone , would these inner bowl seals being bad allow unmetered fuel into the engine since the fuel wouldn't be drawn through the main jet. Seems to use a lot of fuel.

 

[racerone]

Sorry I do not know how much " a lot of fuel " is , so I can not give an answer to that question.

 

[Wetwilly62]

About 2 gallons in 30 minutes at approx. 1200 rpm

 

[Wetwilly62]

Motor is on a 15.5 Fisher marine 1977 , under pretty much no load.

 

[oldboat1]

would do the analysis and fixes systematically (one fix at a time, then test). Could be carb, ignition or both. Seems like a lot of fuel.

 

[Wetwilly62]

Thanks will do. I thought it seemed like a lot of fuel for just a little off idle . Will post progress

 

[F_R]

To answer your question, yes that bad gasket in the center of the float bowl can be the problem by by-passing the main jet. In your other posting, you mentioned running it in a barrel. Is that what you are doing? I can't imagine running a 55hp at high speed in a barrel (!!??!!)

 

[Joe Reeves]

(Post #1)

Working on 55hp 1977 Evinrude, starts and idles great. Bogs down at wot. Compression 158 /164. New fuel lines and pump. Plugs gapped at 0.40. Sparks jumps 7/16 gap. Seems ok until about 1200 rpm then Boggs max rpm about 1800. Leaf plares look good. Carbs have been gone through twice. Have had the trigger and all other electrical components tested. Link and sync good. Read on another post about these loopers and this issue Help please.

(Post #3)

Its giving me a fit. Went back into carbs found inner float bowl seal on one carb cut , and the other doesn't show signs of being compressed. oldboat1 Would this affect it ?

With no intentions of insulting your intelligence, I assume that apparently you aren't cleaning and rebuilding the carburetors properly. Clean them thoroughly and install new complete kits... and clean thoroughly the (2) brass high speed jets that are located in the bottom center portion of the float chamber, way in back of the drain screws. Just one clogged, slightly fouled jet would result in your problem.

 

[Wetwilly62]

I have meticulously cleaned my these carbs with various sizes wire whatever it took to ensure that all the Jets are clear. Can shine a light thru jets to verify clear. Have blown compressed air through all they all are clear. This isn't the first old outboard that I've redone. The cut inner seals in the fuel bowl kind of caught me by surprise I don't know why it would do that. I'm sure not over torquing the bowl screws. Have removed the Welsh plugs and cleared all those chambers in the small passages in the high-speed chamber and low-speed chamber.. thanks for all of your help I'm new to this forum just trying to get things figured out.

 

[Wetwilly62]

Ran motor on trailer backed into lake today. Seems between new carb inner bowl seals and new spark plugs I have gotten the bogging issue resolved. No bogging at WOT. Didn't realize the difference in spark plugs resistor and non resistor type. Depending on the dealer 2 give me the right ones. NGK s data says not to use resistor plugs in older CDI ignition systems. But then their cross reference chart list a resistor style plug.. next question. While running at wide open throttle water stopped flowing from the upper water exhaust ports is this normal?. Motor has never ran hot and good flow out of upper exhaust ports at idle. New water pump.

 

[Wetwilly62]

UPDATE. Changed spark plugs to non resistor type. . No more unburnt fuel in test tank. Now top rpm 3500 . Now motor doesn't sound like its bogging , more like it just stops accelerating.. Rechecked link and sync.. Going by the book timing should advance to 19 degrees +-1. At 3500 rpm. In neutral or in gear. Problem is it meets spec in gear, however in neutral it does not. Timing light Mark's approx 10 degrees advance in neutral... Not enough adjustment in linkage to correct . Any ideas.

 

[Bosunsmate]

I wouldnt of thought it would matter in neutral as in neutral you should no way have a motor going anywhere near that speed, high idle at the very most.
Id try it as it now is

 

[Wetwilly62]

I wouldnt of thought it would matter in neutral as in neutral you should no way have a motor going anywhere near that speed, high idle at the very most.
Id try it as it now is

I sure wasn't comfortable revving that high in a tank, just going by the manual. After run on lake with timing light on #2 cylinder noticed intermittent flash , pulled plugs #2 color much much darker than #1 that looked clean compared to it. Believe I have a bad coil on #2 breaking down on power.

 

[Bosunsmate]

Sounds like youve found it.
Yes good instincts, that high rpm blows pistons up sometimes