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Evinrude 48 spl won't go over 2800 rpm help if you can

M

Mod31c

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I work on Diesel engines every day but this is kickin my butt I've never owned a boat and I got a 19 ft Lowe sunbird pontoon with an evinrude 48 spl with trim here's my problem in drive it only hits 2800 rpm with a little bit of power right when u goose it maybe 1 second then it feels a little sluggish all the way to 2800 and reverse will max out rpm and neutral will max out rpm heres what I've done since I bought the boat last month fist time I took it out it ran rough and was leaking fuel out of the top screen of the bottom carb so I rebuilt the carbs the lower carb was severely gummed up and float stuck I replaced float and all internal parts besides the jets which doesn't come with a carb kit then I hooked up the muffs and could not keep the engine running now the set screw was set to 2 1/2 turns out now I had to set it to 3 1/4 turns out to get engine to runs and it runs good without a load on it it will only screw up when in the water I have good spark through my plug tester and I have 95 psi compression in both cylinders and I am using a 50-1 mix ratio the prop has a a few small chips in it. And I couldn't read the pitch on it it's pretty old and the tilt does not work due to a leaking HYdraulic cylinder and I am ordering a rebuild kit for it so when i go down the lake I have to leave it locked in the down position and that was my next move thinking just maybe since the trim doesn't work it may not have enough power to drive through it and like I said I dont know boats but I'm learning so any feedback would be great
 
well im headed out to the lake now I will try that and by drop test im assuming you mean remove a spark plug wire while being wide open i will give it a shot
 
Boobie said:
Correct.............[/QUOTE
Well no luck on the drop test I doubled up on berryman carb cleaner and after running for a few hours it slowly cleaned itself out now I'm running 4100 rpm which is so much faster but I'm not sure what rpm it is sopposed to run
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Well found out today this engine wot throttle needs to run in the 4500 to 5500 range and the engine still cuts out a little bit when hammered down then smooths out at about 4000 rpm I've been trying to fix one problem at a time to see the outcome after the trim cylinder repair kit gets here I will post the results of how high the rom is getting and after the trim i will replace the prop the prop on there i cleaned up it is a 11 x 3/4 - 17 which appears to be a factory prop husler sells and aluminum 12 - 15 which should increase the rpm if being able to adjust the trim has no affect and i will have results soon
 
kimcrwbr1 said:
When you went through the carbs did you replace the fuel lines and clean the fuel pump? If you dont know the history of the motor it`s best to just go through everything now and get to know it good, Can you hold your hand on the head for a slow count of six after the engine has run about ten minutes. Do the throttle butterflys fully open at WOT and did you check the sync and link after you reinstalled the carbs. Make sure the engine is close to 100% as possible and then you can determine the proper trim and if necessary adjust prop pitch for WOT rpms.
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i did replace all fuel lines and vacuum lines and did not clean the fuel pump can you pull it apart without the gaskets and diaphragm? welli'll just order a new repair kit. with my temp gun im reading 160 degrees on the head while idling when fully wot i can move the butterfly about 1/4 inch which i have done by hand on the water and no change and i put the control rod in the exact same place it was and checking the sync im not sure what you mean by that the set crew is exactly 3 turns out on both carbs thats where i found it works the best, down at 2 1/2 turn the engine will start but will not carry an idle and eventually die and primer bulb is alaways hard while running the sparks plugs are oily wet when removed after running and plugs are new
 
need to start a new thread, this is from 2013, if you can , model number, compression numbers, and open air spark test jumps 1/2 in.
 
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