Marine Carburetor Tuning Part 2

In this video, we tune the idle air mixture screws on a Holley 2 barrel carb. This is a similar setup compared to part one, because it has a single metering body. One main difference, compared to some of the other carbs out there, is the 5.0L has multiple vacuum ports to grab manifold vacuum. In part 3, we will talk about other creative ways to get manifold vacuum.
Keep in mind that the manual recommends doing the above process in gear. Holley recommends the test be done in neutral (for manual vehicles). I will conduct this test per recommendations from Holley.
Be careful not to turn the idle mixture screw in past the seated position or you risk damaging the seat or needle. Both the screw tip and the casting seat can be affected.

[@migueljimenez9419]

Amazing video dude literally you have earned a loyal subscriber been trying to get the perfect tune on my 70 thunderbird......

[@crisnewcomer5174]

This was a great 2 part video. I just got a new (used boat) and they put on a new carb. Idles nice, but when I put in gear it dies. I am hoping after I adjust this and tune it will run strong when placing in gear. It is currently idling at 1000 as well. Thanks a lot!!!!! Very good video and well documented!!!

[@micahwaffle4854]

You ever figure this out. Im having a similar problem with a '90 Supra Ts6m

[@HeadStocks]

Great Carb videos Michael ....

[@michaelromer2016]

Glad you like them!

[@vlovewbus]

Love your videos!!!

[@AchikSarih]

Merci beaucoup ❤❤❤❤❤❤❤❤❤❤❤

[@buzzbikegearofficial]

Thank you mate. Hopefully by August I can get it running again

[@michaelromer2016]

Have you started tuning it yet?

[@buzzbikegearofficial]

@@michaelromer2016 not yet. On Friday the gauge should arrive and on Saturday I'll have my last exam. I'll give it a try on Sunday. Got a 93' cobia challenger 187 with a 3.0 engine. Think mine needs 3 1/4 turns out according to the big manual with about 600 pages. Dropped you another comment on that. If you need it I can send it to you. Very informative for services of all kind

[@SchroetterDA24]

I have a 92 omc cobra 5.0 Holley 2Brl carb. I have a hesitation going from forward idle to WOT. New fuel filter, cap , rotor, plugs. I turned the idle screws an1/8 out today and it solved on my first run, I stopped three different times and tried it and took off without a hitch. Went back out a couple hours later and hesitation was back. Thank you in advance for your suggestions

[@edwincardenales910]

I’m watching your video here. Super informative. I t into that little small hose you showed first I found a T for that size. I made a video but can’t figure out how to send it to you. It’s not giving me the correct in the green but if I pinch the hose closer to the choke, it goes into the green. don’t know if there’s a leak.

[@michaelromer2016]

Sounds like your hose has a leak. Use worm clamps if you need to seal it better. Please hit that subscribe button!

[@MrTanzersailor]

Thank you Michael. What is that 'little guy' you are taking your vaccum from? I have one but it's not connected. What is it's purpose?

[@michaelromer2016]

Go to part one of this video. Thanks!!

[@longrifle325]

Thanks for the videos! I have a 2007 Volvo Penta 5.0 GL. Last year I had no problem reaching the WOT rpms (4400-4800) on an aluminum 4 blade 14.5x19. I had $1300 of work done (gimble bearing, bellows, tune up, etc.). This year with same prop i could only get about 3600-3800 rpm at wot. I changed prop to a stainless 4 blade 15x15 and can reach 4200 rpm. Trying to diagnose the issue without having to take back to a shop. Going to check all the spark plug wires, and do a fuel treatment tomorrow when I can get to boat. Any ideas of what else could be wrong? Thanks again Rick

[@michaelromer2016]

Try putting the boat in water, trim to a level position. Then while in neutral, tell me what is your WOT RPM. That will tell me if it’s an engine issue or a stern drive issue.

[@longrifle325]

Ok, checked in the water and put it up to beyond 5,000 rpm no problem. Doing a fuel treatment now, checked all spark plug wires and cap (no loose connections).

[@longrifle325]

Michael, any idea where to look for the loss of power?

[@donreynolds6187]

I have a 95, same carb, engine. Had carb rebuilt. Reinstalled it and now in process of reading how to tune it. Came across your video and noticed my linkage is hooked to bottom of throttle and butterfly is closed, engine cold. Due to linkage length I could not installation to top carb connection. How do I adjust butterfly to be fully open?

[@usmarinecorps05]

So how many turns did you end up doing on the idle mixture screw?

[@ericbrinton6224]

I have a PMC Marine engine. We had the holly carburetor rebuilt and it stalls when coming to an idle. It also stalls when planing. I changed the spark plugs & wires. I was told that there is a plate that goes under the carburetor that helps it drain. The boat is a Correct Craft 351 PMC Marine engine. The previous owner took out the electronic fuel ignition because of some issue. So, i am not sure how to solve my problem.

[@michaelromer2016]

Sounds like a carb. issue. Watch this video and follow the steps. kzbin.info/www/bejne/oZOslXeQo8emf7M

[@joseterriquez3656]

Can the carburator be replaced with a new one?

[@michaelromer2016]

Yep!

[@Reed6510]

Michael. Followed your video and rebuilt my carb on a 89 OMC Cobra 5.8. 1st time out it ran great. 2nd time out it did not want to go past 2500 rpm. Would not plane out. Finally got it to work playing with throttle. Later in day it acted up again. Any thoughts on where to look ? Thanks Bill

[@michaelromer2016]

Put your vacuum gauge back on it and try again. It should be able to reach WOT while on the trailer. If it’s only doing it on the water, check your floats.

[@Reed6510]

Thank you

[@Skywagonwest]

Shouldn't you do this tuning with the flame arrester installed?

[@michaelromer2016]

The manual calls for the flame arrester to be on, likely for safety-Holley doesn’t.

[@ealex1312]

Question for the 4.3gl.... the 2 bbl Holley doesn’t have vacuum lines other than the one to the choke. There is a port in the rear center near the base that is capped off. Is that where I should attach the vacuum gauge?

[@michaelromer2016]

The one in the rear is likely the vacuum port. In part three I will go over where some other places you can get vacuum. Remove that port on a COLD engine and make sure water doesn't come flying out. Testing on a warm engine will cause serious bodily injury.

[@bc2planker]

@@michaelromer2016 I don’t see a part 3, and have the same question about where to attached the vacuum gauge on the penta 4.3GL. Any tips?

[@michaelromer2016]

@@bc2planker what year do you have?

[@bc2planker]

@@michaelromer2016 I have 2001 Volvo Penta 4.3 GL. It has the Holley 2 barrel carb.

[@eaglebro2434]

Do you know what that part is you connected the T to? Mine has the connect port broken off and want to replace it. But I cant find it!

[@multi6781]

Hello Michael, I have a Holloey 4160 marine carburator, can you please advise the kit number for rebuilding this carburator and where is the best place to buy it from

[@timhaisch5275]

Been trying to figure out the carb problem on a 1996 Ski Nautique with a 351 Ford V-8. It will start great but dies with I put it in drive. If I let it idle for 5 min it will go fine. When warm the motor idles around 800 rpm. any ideas? The boat has 290 hours on it.

[@dickdykstra2234]

Michael I'm the guy from a while back, any ideas on why my boat has to crank and crank to start even warm. it's a 91 alumaweld jet with Holley 4 barrel on a 5.8 Red line ,351. Bought carb last year reman. from National Carb.

[@michaelromer2016]

You likely don't have a carb issue. You need to look at the cap and rotor, spark plugs, wires, and coil. Check out my videos on ignition related issues.

[@dickdykstra2234]

@@michaelromer2016 Ok thank you Michael will do.

[@susantroy11]

Thanks for the video Michael, I went out to look at my 1989 5.8 L Cobra but for the l life of me I can only find the pvc hose from the valve cover to under the carburetor no other vacuum hose to the carb can I use the pvc hose to test vacuum? Thanks

[@TheKing-nu4fk]

Same here on my 90 omc 302. Were you able to pull vacuum off that?

[@tristenfletcher577]

I have a volvo penta 3.0 will it be the same rpm

[@usmarinecorps05]

Do you have fb?? I got a question and will pay you for your time.

[@kenivie7422]

40 isn't possible in vacume.