1977 190 OMC stumbling issue

Hello everone , Need some help !! I have driven myself mad and pritnear broke trying to solve this issue. 302 with a 2bbl Holley, I have rebuilt the carb completely, and have changed out everything , in every possible configuration,cleaned and assembled at least 40 times (seriously), now the gaskets are history, accelerator pumps, power valves, jets, squirters, It allways stumbles from 500 rpm to 1000, once you put it into forward it stumbles ( like its starving) and quits, after 1000 it works great, if you give it a quick shot it works fine, but you don't dare do that in the channel, today I installed a mallory distributor with a Pertronix flamethrower conversion kit, coil,cap ,rotor,wires and A/C MR43T plugs and gap of .40 10 degrees adv. total 28. Did voltage tests, vacuum leak tests , gauge does fluctuate 17-20 . compression is in the 125 range, no missing or any other issues. prem. fuel. I just can't seem to get it ! intake gaskets ? weak fuel pump? I'm almost certain its the carb but i don't have another to try or the 350.00 for a reman. If there is a WIZARD out there could you help, I'm going in to get a couple Advil and will come right back. Thanx David.

Welcome aboard !

Just your bad luck i always go to bed at 11 pm every night. But i'm up early.

I like the sunrise always do, and love hunting for the reason above and fishing and being on the water and watching the sun rise.

Are you calm now ?

My sweet talk get you to relax ?

No i ain't gay, i have a gorgous wife of 25 years and 4 kids so don't worry !

Ready to fix it ?

Lets look at other issues that might affect your motor.

You have sticking valves. Your vacuum test tells me that. What it also tells me is your a good mechanic.

So you ready to indulge me.

1-You tried setting idle in the water, warm engine in gear, to 600-700. Try 650.

Your idle is set at 500, in the water, warm engine, in gear ?

You posted ( It allways stumbles from 500 rpm to 1000 )

You post back and we will go from there.

Don't give up we all here WILL HELP YOU !

12splash said:

once you put it into forward it stumbles ( like its starving) and quits,

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does is tumble and stall the same way in Reverse?

chiefalen said:

Welcome aboard !<BR><BR>Just your bad luck i always go to bed at 11 pm every night. But i'm up early.<BR><BR>I like the sunrise always do, and love hunting for the reason above and fishing and being on the water and watching the sun rise.<BR><BR>Are you calm now ?<BR><BR>My sweet talk get you to relax ?<BR><BR>No i ain't gay, i have a gorgous wife of 25 years and 4 kids so don't worry !<BR><BR>Ready to fix it ? Lets look at other issues that might affect your motor.<BR><BR>You have sticking valves. Your vacuum test tells me that. What it also tells me is your a good mechanic.<BR><BR>So you ready to indulge me. <BR><BR>1-You tried setting idle in the water, warm engine in gear, to 600-700. Try 650.<BR><BR>Your idle is set at 500, in the water, warm engine, in gear ?<BR><BR>You posted ( It allways stumbles from 500 rpm to 1000 )<BR><BR>You post back and we will go from there.<BR><BR>Don't give up we all here WILL HELP YOU !

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Hello Chiefalen, I have had the boat to the lake 2 times only to be leashed to the boat ramp, 20.00 per launch, they won't even give a guy 15 min to do tests, so now i've got the outdrive in a large rubbermaid bin, any attempt to increase idle results in studder, i have been over the motor with remote starter switch and throttle cable removed so i can respond with quick actions to keep it running, attempts to control from helm are useless, as for sticky valves i used a can of seafoam, and a quart of dextron, @ 1000 rpm or more you would notice a sticking valve wouldn't you ? It comes to life in a big way ,above 1000, like it was new ! I also forgot to mention i have worked on it every day for over 2 weeks! wife a kids are ready move on to another dad with a running boat ! I'm about ready to throw in the towel !! ( a gas soaked one !!!!!!!!!) ADVIL SURE HELPED ! Tuning a 10 sec CHEVY Nova is childs play compaired to this!<BR><BR>

hystat said:

does is tumble and stall the same way in Reverse?

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yes it does, I have the shifter/ throttle cable off at the carb to fiddle , just after you break the idle circut it starts to stumble, you need to flutter the throttle to make it recover or crack it to keep it going. After some thought ,I'm starting to think it isn't the carb at all ! I have the same outcome no matter the set up in the carb! the new plugs are gold in colour.

try a compression test could be a burnt valve

125 on all the cyl. first post.

timing chain loose; and sticking valves ?

I realize this is a month old but have you checked your accelerator pump nozzle?

Does this have the electric shift assist?

not if it's a electric shift and that.s what i think he has.

Maybe wrong carb ?????

Beg borrow or steal another carb to test on this ole piece of iron.

Never replied to my questions.