Top speed with 18hp Evinrude on 14′ aluminum

[westwind]

quote outbdnut2:

I had a cheapie compression gauge a few years back that had the check valve at the far end of the rubber hose (the cylinder end), so unless you were measuring a big cylinder, like in a big car engine, the volume of space in the hose between the checkvalve and the gauge offset the readings down significantly. Be sure you don’t have that problem. I tossed that one out.

Nothing wrong with having a hose. It just takes a couple more revolutions to get to full pressure on a small motor. No need to toss it for that.

[stephenspann27]

I appreciate all the expert info you guys gave. I’ve got another project (motorcycle) that I need to finish to free up space in my garage before I get back on this 18hp. I am glad to know that it was running at probably half power because I’ve been really disappointed in the power. I’m looking forward to running it with it running 100%.

[Mumbles]

Your 18 should push your Lone Star faster than 16.5 MPH.

Here’s three different 18’s on a 14′ McCulloch with just myself in the boat and they average out around 25 mph.

https://www.youtube.com/watch?v=p96DIKwaR9E

https://www.youtube.com/watch?v=p16PzP5bvRc

https://www.youtube.com/watch?v=pxLdVbqhC_g

[wiscoboater]

Hang in there Stephen, You’ll find a good power head. Post an ad here like Ben Mentioned. The Guys in the club have all kinds of stuff stashed away in shops, garages and basements. Craigslist can help too. I’ve found some great motors there, but some real stinkers as well. If you go look at one… take your gauge and a plug socket with you. If the buyer won’t let you test it, he and the motor are not worth your time.

[wiscoboater]

Hey Stephen, one more thing. You stated the upper plug was white while the bottom was brown. You may want to check that the top hole was even firing. That sounds like a dead fuel washed plug to me.

[fleetwin]

Looks like I have missed a lot on this thread in the past few days….
First, Bill is absolutely right, good compression readings do not guarantee all is right with your powerhead.
I am confused by all your pictures and postings at this point. You have several pictures of horrible looking scored pistons with jammed rings. Needless to say, these parts are not usable and can not be "repaired". The corresponding bores are surely damaged as well. My question is which powerhead did these pistons come from? The original blue powerhead, or the replacement white powerhead? Or, do both powerheads have bunged up pistons and bores?

[stephenspann27]

quote wannabe outboard guy:

Hey Stephen, one more thing. You stated the upper plug was white while the bottom was brown. You may want to check that the top hole was even firing. That sounds like a dead fuel washed plug to me.

I did verify both cylinders still had spark. I"m wondering that on the compression stroke, as the piston is approaching TDC is the fuel/air mix just blew past the rings before the spark plug was firing.

[stephenspann27]

quote fleetwin:

Looks like I have missed a lot on this thread in the past few days….
First, Bill is absolutely right, good compression readings do not guarantee all is right with your powerhead.
I am confused by all your pictures and postings at this point. You have several pictures of horrible looking scored pistons with jammed rings. Needless to say, these parts are not usable and can not be “repaired”. The corresponding bores are surely damaged as well. My question is which powerhead did these pistons come from? The original blue powerhead, or the replacement white powerhead? Or, do both powerheads have bunged up pistons and bores?

The blue powerhead is what my outboard came with (as a project), I learned it was trash after tinkering with the motor a long time. I bought the white powerhead off ebay to replace the blue one but it turns out it is bad too. I haven’t taken the white one apart yet, but I did remove one of the covers where the fuel pump bolts and posted a photo of the side of the piston through that hole. It looks like the motor has been hot. The thermostat was also removed when I got the white powerhead.

[fleetwin]

OK, so the white powerhead has bunged up pistons/cylinders also. I don’t suppose you could return it, probably too late…
I’m sorry you are having such terrible luck, wish I had a decent powerhead for you…

[dan-in-tn]

I have oversize pistons & rings for your motor if you would like to rebuild what you have. It is one option. It can even be bored down here in TN if need be. Just let me know if you are interested?

Dan in TN

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