87 140 Rude

I have a 87 Evinrude 140 Looper on a 21 Proline WAC. Just had a complete tune up, carbs rebuilt etc. Shop put 70 jets in and said it ran great. They said it was done and I could get it, picked up boat put into water. Started and idled great, would not get on plane. Called them and tech came to water and said it was running fat, he said bring it to shop and I'll put in 65 jets in and you'll be fine. So they did that. This time tech came for boat ride and same thing. On the water we took off the cowl and removed carb box cover and ran boat. It jumped up on plane with 3 men onboard like nothing, doing 28 knots @ 5000 rpm. As soon as carb cover reinstalled bogs right down. We even went down to 61 jets which I believe are what the factory spec suggets. The tech says maybe there may be a crack in one or more of the carbs but the way it ran without the cover seems to dispute that theory. Any suggestions and help would greatly be appreciated, I'm going nuts!!

Kenny

Re: 87 140 Rude

actually it sounds like it is getting too much gas. with the cover off the motor is drawing more air. that is the reason, they say do not run with the cover off, and the extra air leans out the fuel air mix.

Re: 87 140 Rude

Tashasdaddy,
Thanks, we started with 70 jets, then 65 and now were at 61. When you change jets are there other adjustment that shoule be done on carbs too?

Kenny

Re: 87 140 Rude

First of all you need someone to work on the motor that understands loopers. On a recreational motor there is no reason to change jets. Make sure they put the stock jets back in and make sure they are the correct ones ("D" jets, not "C" jets). Taking the airbox cover off of a looper causes it to run 10 to 12 jet sizes leaner. A very dangerous thing, pistons don't like that.

Re: 87 140 Rude

Dhadley,
Thanks, I will be going to the shop Tuesday(closed on Mon). I live up here around Crystal River,FL and haved a difficult time finding a good & fair boat mechanic. It seems they are all learning in the procss and my expense too, or I have to redo it. It seems nowdays very fer pay attention to detail anymore!

Thanks Again,

Kenny

Re: 87 140 Rude

After getting the correct jets in they found a crack in a carb and swapped it out. Runs great now!