The 81 4HP water test result... and a question

[evinrude81]

Well, as promised took it out today on a friends boat and up and down the river, running for a cumulative 2 hours in 3 stretches. Seemed to work very well and started right up (without choke being needed - well, it was a warm and pleasant day here in the San Francisco Bay area).

All went well for except for one thing that I think I puzzled out but would like confirmation. All ran very well for a while, perhaps 40 mins at various throttle speeds, then it mysteriously cut out, as if it had run out of gas. It was easy to restart and it did this several times so I was getting a bit concerned that perhaps the float, being cork, had decided to get saturated with fuel having been dry for ten years or so.

Anyway, I richened the mixture progressively (it was running fairly lean), and after a couple of adjustments, the problem went away and took it off for another 40 min motor down the river to confirm, where it continued to run very nicely.

So just wanted to confirm with you guys - I think the problem I observed was because I had it set too lean. Would I be correct?

Getting very close to some cosmetic improvements!

Thanks again,
Mark

 

[JUSTINTIME]

Re: The 81 4HP water test result... and a question

sounds like it
u should have puled ur plugs to check
better to run rich than lean

 

[evinrude81]

Re: The 81 4HP water test result... and a question

Good point - I should have mentioned that (duh on my part) - I did pull the plugs and they were a pale brown with no signs of fouling. They looked pretty good but supportive of the lean theory I think.

 

[Scaaty]

Re: The 81 4HP water test result... and a question

If you had a sunk float, when it quit and you pulled the plugs, they would have been wet. Your fine....need gas to run!

 

[tashasdaddy]

Re: The 81 4HP water test result... and a question

if you use Joe Revees, carb controls thread all will be well. either 2 knob, or the 1 knob.

 

[evinrude81]

Re: The 81 4HP water test result... and a question

Thanks - that was useful and confirms where I'm set. I'm still a bit puzzled though - why did it initially run for 40 mins without issue while set too lean?

The thing to bear in mind is that this is a motor that had only been tank tested until yesterday, and prior to that had a 10+ year hiatus. Is it possible that, despite my cleaning efforts, it was still a little gummed up in the carb and thus demanding less fuel until it was run under real conditions for a while? I guess this theory would explain by riching the mixture would solve it? I did also not that the engine noise sounded 'deeper' and healthier after this initial period. Still curious if anyone has any thoughts.

Many thanks to everyone
Mark

 

[JUSTINTIME]

Re: The 81 4HP water test result... and a question

sounds like u hit it right on
no u have to adj timing at idle and wot

 

[Scaaty]

Re: The 81 4HP water test result... and a question

sounds like u hit it right on
no u have to adj timing at idle and wot

Timing is fixed, no adjustment

 

[tashasdaddy]

Re: The 81 4HP water test result... and a question

you may have been burning the carbon out of it.