Slow out of the hole

[TightlineT]

I have a 86 Mercury 150 HP on my boat and it has suddenly started being slow to come out of the hole. There is no miss in the engine, just the RPM's won't come up fast enough to pull it out of the hole very quick. Once on a plane, it runs normal rpms with no miss and no problems. I tried some of the Stabil stuff for ethananol and it didn't seem to do much for it. Should I try this seafoam stuff everyone talks about? Plugs seem to look ok to me. Any suggestions appreciated. emoScratch emoBang

 

[fishnboy]

if i run that cheap oil it makes mine slow out of the hole.and have you tryed a bigger prop that turns more rpms comming out of the hole.mabe you have not got the right fuel mix.not anoth air.just some things to think about

 

[TightlineT]

Thanks for the reply. I may have put too much oil in the mix, but it's been happening over the last couple of fill-ups. I may still have it a little rich???

 

[wrechin2]

How much slower? What oil mix are you using? A little more oil will not effect the performane of the enigne enough to tell. Keep in mind 50:1 is only 1% oil and 25:1 is 2% oil. Have you done anything different other than that??? Try another set of plugs. Even though they look good they could be causing issues. Just a thought.....

 

[TightlineT]

Thanks for the reply wrechin2. I haven't changed anything at all. I first thought it may have been the ethanol thing, but if that was the case, all of us would be having the same kind of trouble. It will turn around 2800-3000 rpms untile it finally takes off and gets on plane. Kinda feels like the boat is REALLY loaded down with weight on takeoff. I'll try the plugs and thanks again.

 

[wrechin2]

Change the plugs first........ I couldn't tell you how many times I was called to the lake and the guy change his plugs and it was fixed. I got tired of all the wasted trips. It may be a stator going down. I have posted a page out of my manual for this issue. Look at the part where it states....won't rev past 3000-4000 rpms. It may come and go. I had a stator that I fought with. Boat would run only on 5 cylinders for about 45 seconds and then run normal. You can do a few minor test and see what is going on. It may be mechaical, fuel, electrical. Hope this helps.

Do you have access to a timing light? I can walk you through some diagnostic steps if the plugs didn't help.

 

[puddle jumper]

Along with all the stuff wrenchin2 said,, One other thing that comes to mind, You didnt say much about the boat so im just shooting in the dark, but could the boat be holding a bunch of water for some reason, might be a weight thing,, have you hit anything lately "waterloged hull "?? and have you drained it "plug" ?? If not you might want to check them as well, My boat runs kind of like you are talking about but it from a big live well ive added and it's loaded down heavy...
Puddle

 

[TightlineT]

Thanks to both for the reply. No extra weight or water and I don't think the hull is waterlogged that I can tell. Sometimes it is better than others for some reason. I don't have a timing light, but might borrow one from someone. As for 5 cyclinders, wouldn't I hear a miss in the engine if one wastn't firing? She's smoothe as a button, just hard to get on pad. I think I will try the plugs first and then go from there. Thanks again for all of your suggestions and I'll take anything else you guys can think of.

 

[wrechin2]

Good point. Sometimes it is easy to overlook the obvoius as there are so many possibilites.....

If it drops a cylinder completely, you won't feel it. If it is coming and going you would feel it. With a timing light you will be able to test to see if it is dropping any cylinders. Try th plugs first and see what happens.

If the oil system has been disabled it will be a NGK-BUWH or Champion L76V. If not it will be a NGK-BU8H.

Later