Need help troubleshooting high idle problem.

[wellcraft-classic210]

Another opportunity for the experts to offer advice // Upload pics to most anything that will all you to provide public links is 1 option


I seems you might benefit from looking at a motor in another boat from a similar year -- And that used parts from a yard might help keep some costs down.

If you tell us the year per the prior request we may be able to help with pics.

Thunderbolt is mercury's marine ignition system -- it's what you should have // You will also want a shift interup system which is tied to the ignition system ( you may have that but its hard to say without the pics

 

[Bt Doctur]

the block the wiring attaches to uses 1 bolt isolated from ground for the green/white wire and the actual mounting bolt for the block supplies the ground connection.Red is the long mounting bolt that supplies a ground and has the black wire, green arrow is where the green/white wire goes, a short screw

 

[Scott Danforth]

im coming in a bit late here and based on the one pic, it looks like someone pulled a complete motor from a 1974 or older truck or car motor and dropped into your boat.

not only does it appear to be an automotive dizzy, it has the slide window for adjusting points.

post a pic of the top of the carb and the whole motor

the other thing that I would assume, they did not install marine head gaskets or brass core plugs, most likely they did not install the marine circulating pump and it probably has the automotive starter and alternator on it too.

sometimes the only way to re-seal a can of worms is with a bigger can.

 

[Eastboundndown]

Thx everyone, I checked the starter, alternator, Circe pump, brass plugs and that stuff seems legit. I have the neutral safety switch on control board connected as shown in diagram.. thank you for verifying that for me though.. I originally hooked other end up to - on coil but the coil seemed to get boiling hot so I thought I had erred on my part and disconnected it.. now I’m thinking maybe the pick up, points or breaker in distributor we’re not functioning properly so coil wasn’t discharging or maybe working harder from constantly discharging.. or maybe condenser wasn’t cleaning up the mess and there was a lightning storm going on in there.. I also removed carburetor today and bought a rebuild kit.. looks like I was right about the air/fuel mix needle.. some meat stick buried the thing so deep in the carburetor that it’s a complete different shape. Just hope damage was done to needle only.. I will try again to figure out how to post pic.

 

[Eastboundndown]

So I have 9 photos on my idea board under WOT.. that should help paint a picture of what kind of **** show I’m dealing with. Thx again everyone

 

[Eastboundndown]

https://www.iboats.com/ideabook/wot-idle/117476

 

[wellcraft-classic210]

Hmm -- Nice " vintage " cruiser-- What year is it ???

Seems like getting the carb. cleaned up and a new dist. would be a good start to see how it runs.

You may want look for any open ports on that intake or the Vacuum hoses at its seems you may have a fairly large vacuum leak somewhere.

 

[Eastboundndown]

It is an 87 and you are correct. Found a hose adapter fitting installed in intake manifold and I’m guessing it was put there to run vacuum to auto distributor that was installed.. I also stumbled upon a thunderbolt IV V822 module in the cabin behind a seat cushion while tracing some wires out......... I also found the remains of what appeared to be the original dizzy but just housing, rod and gear no cap, rotor, plate or electronics.. so I put a call to the gentleman that’s responsible for creating this mess to find out if module was junk and he says.. no it’s good!...? why? Really?? cuz why wouldn’t you disconnect it, throw it under a seat cushion and decide that today would be a good day to turn your vessel into an automobile...!!! Soo.. in the meantime I have been making the occasional visit to local marine graveyard and have scored a brand new-like Edelbrock 1409 carb.. It looked fairly new from the outside and when I took it home I opened it all up and was absolutely shocked because it looks like it has never been used which then kind of made me nervous because I have read a few posts from people saying that Although they are great carburetors some people had to drill out excess weld because they were blocking jets or something like that but I have it in now and it’s spraying nicely sooo. I think I should be good.. now I just have to figure out what to do about ignition system. The way I see it I have 3 options.. I can try finding the rest of the dizzy at boat yard or marine supply for the plate, sensor, cap, rotor and harness.. and hope that the old tbolt module works and even if it does for how long? summit has a marine electronic ignition kit for around 350 that comes with everything I would need.. except wires if it’s HEI, or a DUI plug and play Dizzy.. for around the same amount.. would love some advice or input from anyone with which direction may suit me best. Thank you

 

[Eastboundndown]

https://www.iboats.com/ideabook/thunderbolt-iv

 

[Eastboundndown]

So got her started and running... ok. I still have auto dizzy in because before I sunk any more money into it I wanted to be sure it ran okay.. so I have put a like new Edelbrock 1409 carb in. Removed hose adapter from top of intake.(used for auto vacuum advance I would assume), Removed vacuum advance from dizzy. Cleaned up points, cap, plate and rotor. Cleaned up all electrical grounds to motor. checked to make sure my balancer marker for TDC was right.... which it was not so I reset to TDC . Used jb weld on dizzy to seal space left from vacuum removal and installed dizzy, new plugs and wires. Got a fresh can of gas and fired her up. And she fired up....We’re making progress. Still not running as smoothly as it should but we have something to work with. Just wanted to update to all that helped me during this. Thx

 

[wellcraft-classic210]

Sounds like your making good progress !!!!

Good score on the 1409 ! It may require some jets to be setup / Kits are available with a variety of metering rods. I have sen posts where people pull and read the plug colors after different RPM range runs to verify the proper fuel mixture. Wish i did that back in the 80's on my hot-rod nova that poured black smoke when I got on it hard -- In other words that happened most of the time I drove it.

As far as I know the thunderbolts were a good reliable design -- I would probably go that route to keep it stock if its not too costly --

But again the experts may have added advice.

 

[thumpar]

You mentioned the neutral safety switch. That is not what we are talking about when we say shift interrupt. The shift interrupt cuts the ignition for a split second when shifting out of gear under load. Without it the drive would take a lot of force to get out of gear.

 

[Eastboundndown]

You mentioned the neutral safety switch. That is not what we are talking about when we say shift interrupt. The shift interrupt cuts the ignition for a split second when shifting out of gear under load. Without it the drive would take a lot of force to get out of gear.

Im sorry, I believe I used improper terminology.. was referring to the n/o micro switch that is supposed to interrupt power when shifting into gear.. Sry about that... all this is very new to me and sometimes I get mixed up.. so what is the neutral safety switches function because I was definitely referring to the shift interrupt... I think?! Lol

 

[thumpar]

You mentioned the neutral safety switch. That is not what we are talking about when we say shift interrupt. The shift interrupt cuts the ignition for a split second when shifting out of gear under load. Without it the drive would take a lot of force to get out of gear.

Im sorry, I believe I used improper terminology.. was referring to the n/o micro switch that is supposed to interrupt power when shifting into gear.. Sry about that... all this is very new to me and sometimes I get mixed up.. so what is the neutral safety switches function because I was definitely referring to the shift interrupt... I think?! Lol

There is a neutral safety switch in the controls that keep you from using the starter unless it is in neutral.

I know when I first got into wrenching boats it was new to me. I have always been able to work on cars. Boats are very close in some ways but very different in others as far as engine/drivetrain works.

 

[Rick Stephens]

.. was referring to the n/o micro switch that is supposed to interrupt power when shifting into gear..! Lol

Shift interrupt should only activate going OUT of gear when in the water. Purpose is to unload the gears allowing them to go into neutral.

 

[Eastboundndown]

Sounds like your making good progress !!!!

Good score on the 1409 ! It may require some jets to be setup / Kits are available with a variety of metering rods. I have sen posts where people pull and read the plug colors after different RPM range runs to verify the proper fuel mixture. Wish i did that back in the 80's on my hot-rod nova that poured black smoke when I got on it hard -- In other words that happened most of the time I drove it.

Thanks for the support!! So I read an article on that..actually the article was very informative and it was all about ignition and timing. I am going to attempt to share the link. I had my timing set to TDC when I put dizzy in.. and I was hearing what sounded like spark plugs firing when running and the exhaust fumes smelled unusual.. couldn’t really relate it to something to describe it better ... but not right..So loosened the dizzy bolt an tried rotating it a little in each direction. CC results- higher idle but same or worse spark noise.. clockwise.. spark noise dampened and a lot less prominent but can still be heard.. and idle was consistent and sounds to be in the 8k range but I have no instruments working yet soo that’s a guess. Do you think I should re- set the dizzy to 10-15 degrees btdc. Would that fix the spark noise that almost sounds like a fuel injector noise/ valve tick.. I noticed the metering rods on the carb felt rough in a few spots about a little less then 1/2 way up like they were scratching up against the walls or hole might not be lining up 100% where top and bottom halves of carburetor meet., or maybe it’s nothing and doesn’t matter.. I only mention it because I don’t know.. I believe the springs were orange.. but I have no idea what size metering rods themselves are., and I have no idea how to set A/F idle screws on carb. I think I set them in till they were pretty tight then turned them back 2 full turns... maybe half turn more.. Another words... I still have a lot to learn and figure out so I welcome all the help I can get!! Thx

 

[Eastboundndown]

There is a neutral safety switch in the controls that keep you from using the starter unless it is in neutral.

I know when I first got into wrenching boats it was new to me. I have always been able to work on cars. Boats are very close in some ways but very different in others as far as engine/drivetrain works.

I just learned more stuff.. thx for clearing that shifting/ starting control thing up for me.. I bought my Ram truck new in 07.. only has 70k mi. On it cuz mostly in my E350 but I just found out last week about that..(as I went to start my truck that was left running by mechanic after inspection for new sticker ) I had that terrible nail on the chalk board pose and.... nothing... pretty sure my vessel presently would not fare so well.. lol also figured out how the quote works for replies.. yup... no more copy and past for this newbie!!

 

[Eastboundndown]

Okay all.. I’m proud and happy to announce that I successfully installed a thunderbolt IV ignition system including a new distributor with electronic or maybe magnetic pickup.. but regardless no more auto dizzy.. I also found an Edelbrock 1409 in almost perfect shape.. A few hours of digging in Conex boxes and right around 275.00 for ignition system, dizzy, new cap rotor plugs and carb.. and she is running sooo much better, I think I will hire a mechanic to fine tune the carb, timing and thunderbolt system and she should run perfect... happy happy happy.

 

[Eastboundndown]

I couldn’t of done it without everyone who helped so once again... thank you!

 

[Eastboundndown]

Next up.. not a single wire for hydraulic equipment is connected. Could desperately use a wiring diagram.. I know there has to be one in here somewhere just not sure. Early 80s mcm generation 1 5.7 with alpha 1... I think.. boat is an 87 chaparrel