RPMs won't go up

[WATSONBLS]

Hi, I have a 1966 Merc cruiser Chevy block 120hp inboard/outboard engine. I recently put a new Carb and fuelpump on it. When the it's in neutral the engine revs up fine but when it's in gear, the RPMs won't go high enough to go over 5 or 10 mph. Any Ideas? Thanks for any help.

 

[Don S]

Re: RPMs won't go up

Has it had it's yearly tuneup? How about the fuel filter? any water in it? Any restrictions in the fuel tank pickup or tank vent?

 

[Bondo]

Re: RPMs won't go up

What size Prop is on it,..???<br />Is the Outdrive the Original,..???<br />Is the Gear Ratio in the Drive 1.98/1,..???<br /><br />How Fast a motor will Rev without a Load is Totally Irrevelant to Anything.........<br />That motor,... Runing on Only 1 or 2 cylinders will Still Rev to 5000rpms without a Load.............<br /><br />Just What Does it do when trying to accelerate,..???

 

[waterone1@aol.com]

Re: RPMs won't go up

Normal maintenance items as above come first. If still not performing, time for a compression test.

 

[WATSONBLS]

Re: RPMs won't go up

No, I haven't tuned up everything yet. When the old carb and fuel pump were on it, it ran right. I've been told it could be the points, Ive also been told it could be the fuel/air ratio on the carb. The out drive is original. I'm not sure on the prop size or the gear ratio but regardless of all that it should still go above 5mph. also, it ran right with the old carb. I did change the prop with one that came with the boat when I bought it but I think it should still rev up better in gear.

 

[Don S]

Re: RPMs won't go up

it ran right with the old carb.

Well now, I guess that pretty much narrows down where the problem is, doesn't it.

 

[WATSONBLS]

Re: RPMs won't go up

It did run right with the old Carb. Except that it would flood itseld out every 5 min. Do you think that it would run different in neutral and in gear if its the carb?

 

[WATSONBLS]

Re: RPMs won't go up

If it is the air/fuel mix, does anyone have any advice how to set it write? Or should I just keep twisting the screws untill it runs right?<br />Thanks again

 

[Bondo]

Re: RPMs won't go up

Originally posted by WATSONBLS:<br /> If it is the air/fuel mix, does anyone have any advice how to set it write? Or should I just keep twisting the screws untill it runs right?<br />Thanks again

You need to Remove the Carb,.... And Rebuild It.......<br /><br />Then,.... Maybe,..... It Might Run Right........<br /><br />It Sounds like you've gone from Too Much Fuel,... To Too Little Fuel..............

 

[muc]

Re: RPMs won't go up

"I did change the prop with one that came with the boat when I bought it but I think it should still rev up better in gear."<br />Might want to see if the new prop is the same as the old prop that was on the boat when you got the right R.P.M.s

 

[WATSONBLS]

Re: RPMs won't go up

"You need to Remove the Carb,.... And Rebuild It"<br /><br />It's a bran new Carb, I hope it doesn't need rebuilt. I am thinking it's the fuel mix.<br />Thanks.