Carb issue 1985 Nautique

Alright so I am getting ready to open my boat for the season but I would like to first ask a couple of you for some help on an issue I had last season that I never resolved.

Last season I replaced my spark plugs, wires, rotor and cap. Mind you my boat ran fine before I did this, I just figured its been about five years and time to replace them all. The old wires where tied together and I didn't have an issue, so my new wires I also tied together when I installed them... Needless to say My boat started right up with all the new wires, plugs and cap, but then it would only really run and an idle speed. When I would put the boat under load it would upfire thru my carb and die out. I was puzzled so I called my local mechanic drove my boat to him and he said the carb was missing seals had poor vacuum and the distributer was off slightly but he said it was rusted in place and didn't want to try and wrench on it in fear of busting it, so he left it alone. He rebuilt my carb put new seals etc etc. He said he was surprised the carb got me all these years with no issues. So I spent my 600.00 bucks and took my boat home.

Launched my boat and started up and put the boat under load and of course same issue, up-firing thru my carb again. I called my mechanic back brought my boat back to him for him to look at it. He was puzzeled so he said he did a few more carb adjustments and sent me on my way. Launched the boat when I got home and sure enough same issue up-firing thru the carb again under load.

So i googled and googled the internet for solutions and came across someone said about making sure wires are not touching, So I went and bought a couple plug wire separaters for kicks and started my boat, and amazingly it worked. a small couple buck investment fixed my issue. I called my mechanic and told him what I did and he was surprised that the new expensive mag wires I bought from SKidim would cause a crossfire.

So anyway he came to my lake and water tested the carb to do some fine adjustments and we where all good. Later in the day I was doing some wakeboarding and my boat would choke up trying to pull a skier out of the water, I really had to nurse the throttle each time I pulled up a skier, Once the skier was on plane the boat was fine and ran great. I had to do this the rest of the season.

The odd part is that if no skier was being pulled I could jam on my throttle and my boat would launch out of the hole with no issues. My boat only chokes out of the hole when pulling a skier, I cannot be a boat weight issue because when the skiiers are out of the water and in the boat, the boat will still come out of the hole just fine.The boat will reach full throttle and stay there with no issues, its as smooth as an old Cadillac. It will also throttle down just fine and idle just fine. Also from time to time when pulling up the skier out of the hole, not only will it choke out but it will also again up-fire maybe once again.

So any good suggestions on this mystery would be great.

Thank you and yes it is a Holly Carb. I have found videos over the winter about adjusting the "Accelerator Pump" which I have never done before nor have i touched any of the adjustments the mechanic had made.

I am curious about tackling the Accelerator Pump adjustments but then the holly forums started talking about selecting nozzles which I don't think I should have to touch those since my boat ran fine before all the work was done to it. Even with adjusting the Acc. Pump I dont understand why its only an issue pulling a skier out of the hole and not an issue when I am not pulling a skier.

My mechanic is a rich man because of the area we live in is a rule part of Michigan. He is pretty much the only marine mechanic I know of unless I go over an hour out from our cabin. I totally understand a new carb would have ran me about 500.00 but of course hindsite I didn't think it would cost me that much for him to do what he did to my carb.

He did tell me he thought the wires touching could have been an issue before but he was surprised with the new wires doing that and not the old cracked ones I removed.

This spring I do plan to apply to PB blaster to the distrubuter base to see if it will come lose and try to adjust it myself. My mechanic also said he replaced the advance springs in distrubuter with factory ones, So i asked for my old ones back of which he said he no longer had.

I just wish I would have separated my wires and could have avoided all the hassle. Even my own sense knew that its not good to have wires touching but how the boat was before and zip tied wires together from the previous owner I figured it must not be too much of an issue on these boats. It was a very expensive mistake and now im dealt with a headache to get my carb adjusted properly

I am in eastern mid Michigan (thumb area)

H20Xtremes . Where in thumb area ? I live about 15 miles north east of Davison .

Faceplant wrote: H20Xtremes . Where in thumb area ? I live about 15 miles north east of Davison .

My cabin is in a town called Mayville, It is about 30 min north of Lapeer. M24 and M46 intersect.

Yea, I am on Cat Lake

I had a similar crossfire issue when I made my plug wires too neat. (PS, you can make some really slick wire holders using zip ties: https://www.youtube.com/watch?v=Fll_OPtYsJE)

After some googling, I found this Ford TSB. Wires of sequential cylinders routed next to each other can trigger induction firing and touch off cylinders at as much as 90 degrees advanced. I am certain I was experiencing symptoms of this, even with my brand new Mallory 8mm wires.

On the 5.8 351W, cylinders 1 & 3 and 5 & 6 can be problematic. Please note that in the diagram below, they have #1 wire crossing at 90 degrees to #3 and #5 crossing below #6.

Since correcting my wires, my engine seems to run much better.





ISSUE: Engine miss, spark knock, buck/jerk, surge and other driveability concerns may be caused by induction crossfire. This occurs because of improperly routed spark plug wires.

ACTION: If spark plug replacement is performed, the correct firing order and spark plug wire routing is essential to prevent the possibility of induction crossfire between cylinders. Refer to the following procedures for inspection of the spark plug wire routing and firing order. Properly reroute the spark plug wires if required.

Whenever a high-tension ignition wire is removed from a spark plug, the distributor cap, or the coil to perform a maintenance operation, Silicone Dielectric Compound must be applied to the boot before reconnection. Using a small clean screwdriver, apply a thin layer of Silicone Dielectric Compound on the entire interior surface of the boot. Do not apply compound to metal terminals.

FIRING ORDER:

The firing order for 5.0Ls & all 5.8Ls is 1-3-7-2-6-5-4-8. On these vehicles the #1 and #3, or #5 and #6 spark plug wires must be separated to eliminate the possibility of an induction crossfire.