Fastwin 18 has no power at WOT

Matt Smith · May 3, 2005

First off, I love this site and have gotten lots of help already, but search is not helping me here. Motor is a 1969 Evinrude 18hp. Background: I stripped a spark plug hole the other day after changing a fouled plug. Pulled the head and installed a helicoil. Helicoil fits loosely. Red locktight doesn't hold it. Gonna see if a machine shop can pin the insert to the head. Anyway, I get the new plug snugged up and take it for a test run. Idles rough and has trouble getting to full rpm's at WOT, but when it does, it happens suddenly. Motor ran fine up until the spark plug fouled on me. Both cylinders are getting fuel. Any thoughts?

OBJ · May 3, 2005

Re: Fastwin 18 has no power at WOT

Yep....probably dropping the cylinder with the buggered up hole. Get the machine shop to fix it. Did you put a new head gasket on and torque to specs? Gotta do this. And welcome to the iboats forums VF!! Voted best watercraft site by Forbes magazine.

Matt Smith · May 3, 2005

Re: Fastwin 18 has no power at WOT

Yep. Torqued new head gasket to 18 ft. lbs

OBJ · May 3, 2005

Re: Fastwin 18 has no power at WOT

Strange a new helix coil would be lose. Did you set the coil good after it was screwed in or is it one of those that you don't set with a special punch? The ones I use have a small extended lip. Once in the hole, I use a special punch that flares that outside lip around the hole. Works good.

Matt Smith · May 4, 2005

Re: Fastwin 18 has no power at WOT

It wasn't a coil. It was one of the inserts in the Sav a Thread kit. Yes, I used the included punch.

Matt Smith · May 4, 2005

Re: Fastwin 18 has no power at WOT

OK, I got a helicoil installed, locktighted, retention ringed, and double pinned today for the grand price of $16.39. I'm going to let the Locktight cure for 24 hours before I even think about putting a spark plug in. I'll post back with the results.

Matt Smith · May 5, 2005

Re: Fastwin 18 has no power at WOT

I put the head on today and torqued it down to 18 ft. lbs. Ran the motor in a bucket of water till it warmed up good. Everything ran smooth. I let the motor cool for a couple hours and torqued the bolts back to 18 ft. lbs. Motor runs much better! Will try it on the lake tomorrow. Watch out crappie!

Matt Smith · May 6, 2005

Re: Fastwin 18 has no power at WOT

Went to the lake today. Motor won't make power under load unless I just hold the throttle open all the way and wait. Eventually it will suddenly have all the power it could possibly have and run fine until I back off the throttle. Could this be a fuel issue? Do these motors have fuel filters?

CATransplant · May 6, 2005

Re: Fastwin 18 has no power at WOT

Sounds like a fuel supply problem, for sure. Could be the fuel pump. I'd make sure it's working OK before going much further.

Paul Moir · May 6, 2005

Re: Fastwin 18 has no power at WOT

Do a quick spark check too - I've had engine's with the same sort of symptom caused by cracked ignition coils. It's easy enough to check - just rig up a spark gap somehow and try to draw a 3/8" long arc off each plug lead. If one can jump that, but the other can only jump 1/8" or so, you've found the problem. A good simple test for the fuel pump, carb needle, and fuel line air leaks (sucking air) is to simply pump the primer bulb while it's miss-behaving. If there's no change, you can virtually rule-out all those things. If it improves, it could be the fuel pump or air leaks. If it runs worse, it could also be the fuel pump or the carb's needle. Hope this helps! EDIT: 18 ft/lbs is far too tight. The correct torque is 8 to 10 ft/lbs. Note that you really shouldn't be using a ft/lb reading wrench for that sort of torque range. They tend to be totally inaccurate at the low end of their scales unless it's an *extremely* expensive wrench. Use an inch/lb reading wrench for this.

Matt Smith · May 9, 2005

Re: Fastwin 18 has no power at WOT

Uh OH! Everything I've read here indicates that the proper torque is 18-20 ft lbs. Could I back the torque off to 10 ft lbs and be ok, or should I get ANOTHER new gasket?

Matt Smith · May 9, 2005

Re: Fastwin 18 has no power at WOT

ttt

Paul Moir · May 9, 2005

Re: Fastwin 18 has no power at WOT

I don't think it'll be a problem at all - just back the bolts off (completely, and all of them) and re-torque them. Just try not to upset the gasket sealant while they're loose. Follow this pattern: ..7-8.. .3 o 4. ..2-1.. .6 o 5. .10-9.. (That should look something like a head)

Matt Smith · May 10, 2005

Re: Fastwin 18 has no power at WOT

I have made a mistake. The reason I "fouled" the plug was because I mixed the gas ratio to 25:1. I have since drained the gas tank and replaced it with new 50:1 gas. I have also drained the fuel lines, so I know the motor is getting fresh fuel. Here comes the light at the end of the tunnel: I ran the motor at idle and pulled the boot to the top plug. The motor cut off. I pulled the boot on the bottom plug, and the motor continued to run. I have a manual coming tomorrow by UPS, but am I looking at a bad coil here? A combination of gas that was too rich coupled with a bad coil seems to be the culprit. Could that be the reason I thought the plug was fouled?

Matt Smith · May 10, 2005

Re: Fastwin 18 has no power at WOT

Welp. I had to get out the beer this evening. I pulled the flywheel to look at the coils, and couldn't see a crack in either, but I did notice a white wire had come loose from its screw terminal so I stripped the wire back and reattached it. Buttoned everything back together, fired 'er up, and $%^*@#*#$! STILL no spark on the lower plug!!!! <<<FOUR exclamation marks for emphasis! I'm going to wait on the manual to see how to test the coils and what Ohm reading they should have before I take this any farther. I just hope no one gets between me and the fridge tonight...

Matt Smith · May 11, 2005

Re: Fastwin 18 has no power at WOT

I put two new coils on today and still have no spark on the lower cylinder. Surely someone has some advice...

Fastwin 18 has no power at WOT

Cadet

Supreme Mariner

Cadet

Supreme Mariner

Cadet

Cadet

Cadet

Cadet

Admiral

Admiral

Cadet

Cadet

Admiral

Cadet

Cadet

Cadet