Runs on Trailer, Not in Lake!

[briancraft]

I bought a 70's Raycraft with a 60HP Evinrude. If I hook up the waterhose to it, the thing fires right up and runs like a champ. When I drop it in the lake I can't get it to run. . .it is almost like it taking in too much water as dumb as that sounds.

Any suggestions?

The only variables I can see changing in the water would be the angle of the fuel lines and the fact that the engine is fully submerged in water. . . . . . It's driving me nuts!

 

[ezeke]

Re: Runs on Trailer, Not in Lake!

You are probably dropping [not running] one cylinder.

You don't notice it with no load - on the trailer, but it shows right up when the boat is in the water.

Do a compression test and spark test first and see what the results are. Do the tests with all spark plugs out.

Also the starter needs more power when there is a load, so make sure you have a fully charged battery.

 

[F_R]

Re: Runs on Trailer, Not in Lake!

Backing up what ezeke just said. That is a sign of a sick motor, not running on all cylinders. Can be a compession problem (first thing to test) or ignition problem (second thing to check) or a plugged carburetor (third)

You are correct in that it is because of being down in the water, creating back pressure on the exhaust.

 

[tashasdaddy]

Re: Runs on Trailer, Not in Lake!

another possibility is the idle was set, while running on the hose. this does not apply any back pressure, to the exhaust, causing your problem. try setting the idle up higher. in the water in gear it should be at aroung 650 -750 rpms. i do recommend doing a compression check, all over 100 psi, and with in 10% of each other is acceptable. and check you spark with a cheap spark tester from the auto parts store.

 

[briancraft]

Re: Runs on Trailer, Not in Lake!

thanks fellas, very helpful.

 

[briancraft]

Re: Runs on Trailer, Not in Lake!

one other question. . if it is the cylinder that needs to be replaced do you know what a ballpark estimate would be for how much someone should charge? I am one of those guys that feels like they hand him a tube of KY Jelly as soon as I walk into any mechanic . . . .

 

[mikesea]

Re: Runs on Trailer, Not in Lake!

don't jump to the worst case scenario,dropping a cylinder basically means one or more are not firing,it's usually due to no fuel ,which is probably a carb prob,or no spark,which could be a number of things, simplier probs.are bad plug,wire off or grounding .or bad ground to coil,check the lesser of all evils,starting with spark and compression,if your compression is ok,then its spark or fuel,thus not the worst case scenario,if the eng.hasn't run for a couple months or more, ''''i bet your carb or carbs are dirty

 

[reeldutch]

Re: Runs on Trailer, Not in Lake!

well before rebuilding the motor check the compression, spark, and check the idle timing.
was the motor running good before?
when did this problem start?
how long do you have this motor?
there might not be anything wrong or a whole lot wrong.

to rebuild a 3 cylinder will cost you about:

600 to 700 dollars if you do it your self.
3 pistons 300
machine shop 200
gaskets,seals and other stuff 100
waterpump/tstats/carbkits 150

something like that
about 2000 if a wrench does it for you.

 

[steelespike]

Re: Runs on Trailer, Not in Lake!

Brian, Don't panic.Do your compression check 100 psi is
ideal though the motor will function on less.Being within 10% cyl. to cyl. is the important part.Check the spark
should jump at least 1/4 inch,be a nice blue and you should hear it snap.
If the compression is off a little a decarb treatment may bring things into line.
Look for oily deposits under the flywheel if they are present it could indicate a bad crankshaft seal.Let us know what you find.