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Newbie Here & need help!!!

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nightarcher

Member
I just bought my first airboat,and I have a million Questions!
1988 panther 15x7
19?? Continental 220 6 cylinder gpu
direct drive 2 blade whirlwind prop, good polymer on bottom
this boat will be used for bowfishing
I am having trouble getting it to run correctly, I went to the local airport and talked to a mechanic and he seemed to be VERY vague!
I do not have a bunch of money to spend but I want to do what I can, here are some of the probs, It seems to be fouling plugs, it had a holley 750 carb on it but it is leaking fuel everywhere so I put a edelbrock 600 on it and now after running a couple hundred yards on plane it starts to choke out or cut out??? also when it starts that it heats up really quickly!! can you guys help me out???
 
If you had a lycoming, I would look at fuel supply, but I am not sure about GPU. Sounds like it runs more fuel through the carb than the fuel pump can supply and it starts heating up due to running lean.

But that is total quess work, but it is where I would start looking.
 
I have heard this exact 220 complaint at least 20 times. It’s almost always one of these two things. Like Pat said it could be fuel so the best way to check that is to install a fuel pressure gauge and watch you fuel pressure as she starts revving down. The fuel pressure needs to stay above 5 P.S.I. A lot of air boats run the cheap clicker type Borg Warner fuel pumps these pumps are junk. They always go bad and people spend weeks chasing what you have described. About 60% of the time it’s the fuel pump. If it’s the fuel pump install a Carter Jeg’s PN# 180-P4594. You also need to do a compression test see if one cylinder is getting weak. A weak cylinder causes the other 5 to work harder. When this happens the boat revs down just like it’s running out of fuel because the cylinders are getting too hot. So I would do a compression test and install a fuel pressure gauge. All of the cylinders should be within 10LBS but on old 220’s this is rare they usually are within 20LBS.
 
You might consider running a complete fuel flow check. That means taking the pickup out of your tank to be certain it is not restricted with gunk. There is usually a check valve at the 90 degree nipple coming out of the tank - it is easily restricted. Then a pressure and flow check through the fuel pump and through the fuel / water separator, finally, a pressure and flow check at the carb. Old lines can collapse inside and old tanks accumulate plenty of gunk. Happened to me on an older tank.
 
well when I bought it the holley fuel pump was leaking out the weep hole so I replaced it when I replaced the carb and I put the same holley pump back on, the fuel is what we have been playin with here lately, turn fuel pressure up and down but no change, what kind of compression should I be safe with when I do the test. Thanks guys I appreciate it.

Aaron
 
How many pounds of fuel pressure do you have? On your compression test you should see around 150LBS of cylinder pressure. I’ve seen 220's as low as 110LBS however it takes at least 90LBS to run. You’re really looking for discrepancy between cylinders. Say if 5 are at 145LBS and ones at 90 you found you weak cylinder this will cause an air-cooled motor to run really hot just like it’s lean.
 
Check the power valve. If it is not opening at the correct vacuum the engine will lean out and overheat.
I run a 500 Holley two barrel. Sounds like you may be running a four barrel. A 470 cubic engine can not use any more CFM than a 500 CFM two barrel can deliver.
I have seen a lot of people try to run four barrels on these motors, most with little success. Also, I run the timintg at 30 degrees.
It sounds like it is running lean. On an aircooled engine like this the incoming fuel provides a LOT of cooling for the cylinder heads. Running lean is a sure fire way to toast the engine.
 
hey thanks guys, Mr. guest I appreciate the info, but I am dumb to motors and I hate to say it I dont know what a power valve is. also recomended spark plugs? and the best gap? I have autolite 386 plugs and gap is 25. also how do you check the mags to make sure they are running correctly and are there manuals for my engine? and where would I find them?
 
his boat cuts out worse with more weight in the boat but it still misses and acts like it loses gas in the carb.the reason he put the new carb on was it was cutting out and we thought it was getting too much fuel.so when we tried the new carb it was still doing it so we changed the leaky fuel pump thinking that was it and then we tried spark plugs but we havent done the compression check
 
Sorry I had not logged in when I was talking about power valves.
I would try to find somone that knows Holley carbs and tell him you need to have the power valve checked. It's not a big job. takes about 30 minutes. All they do is remove the valve and check to find if it opens and at what vacuum. Takes a hand operated vacuum pump.
I'd sure try to get it checked. If the engine is running lean it will eventually start detonating and self destruct. $$$$$$$$$$$$$$$$$$$$$$$
 
Power valves are very easy to check. The power valve in a Holley is what controls the fuel flow thru the main booster. There is a discharge nozzle located in the top of the carburetor us rednecks call them squirters. This discharges fuel from the accelerator pump when you first give it gas. Then you will see the booster that hangs out into the middle of the carb barrel. This is what supplies fuel to your motor, if a jet is clogged or your power valve isn’t working no fuel will flow out of it. All you need to do is remove your air cleaner and look into your carb from the side while your motor is running. Don’t look directly down (just incase the motor back fires) then floor the throttle. You should see the squirter shoot some fuel into the carb and as the motor drops vacuum and starts to rev up you should see fuel flowing out from under the booster. If this doesn’t happen that means either you main jets are clogged or your power valve is blown. Have you done a compression test yet.
 
well I have already replaced the holley 750 with a edelbrock 600 and I was begining to think maybe I put to small of carb on it, I have had it out 3 times. 1st time- ran great! leaked gas all over intake appeared to be leaking gas around butterfly shafts, in the holley. 2nd trip- with new edelberock 600 carb and now leaking fuel pump starting cutting out acted like it was fouling plugs but still did pretty good. 3rd trip-sucked it would not want to get up on plane in deep water etc, etc etc.
 
Dam your all over the place. Are any of your plugs fuel fowled. If you foul a plug on a 220 you loose a cylinder and she will over heat. I still recommend pull your plugs and look at them to see if their lean or fuel fowled while you have the plugs out do a compression test. It’s highly unlikely you will find the problem by changing parts. You need to start at A and end at Z.
 
I will almost guarantee that is the problem we are just not hitting on all the cylinders.we have been working on another guys fanboat so as soon as we get time we will do the compression test thanks for the replys
 
I am going to do compression today, and I want to check my mags and make sure that they are hot is there an easy way to check them and what is good/ bad. Also I am running autolite 386 plugs set at 25 any recomendations on better plugs and better gaps, or am I ok? I appreciate the info guys!

nightarcher
 
If they are bendix mag, this old trick will work if you have good hot mags.

Take the plate off that holds the spark plug wires in the mag. Turn the engine over while looking into that opening. There should be the middle shaft visible with a snap ring on it. As it turns, you should see a spark jumping from the center shaft to the place where each spark plug wire goes in.

This does not work if the mag is not producing a good spark.

The other method is put a spark plug in one wire and turn the engine over while watching it. Should see spark, but it is slow. But that is the only two methods I know.

Good Luck
 
Guys I appreciate all the helpful info- I did the compression test and had 5 cylinders pushing 145lbs and 1 that wont even make a breeze! So I guess that I will be learning how to mechanic in the next couple of weeks or so. Are parts hard to get? are they afordable for good ol country folk??

Thanks,
Nightarcher
 
Bet a dollar on a stuck valve. Should be able to get a good cylinder for around $200.00 easily. I have had several lycomings overhauled and new valves guides installed for around that price.

Heck, you can get a new Superior brand for a Lycoming for around $365.00.

I am sure someone can recommend a place to call. For Lycomings I would check Jurnigan's, it might be a place to start for a GPU.

Good Luck
 
I'm sorry to hear you have a dead hole but I'm glade you found it . Think of how long and how many theories you would have chased if you didn't do a compression test. Even when you don't know the answers you will always find the problem quicker if you start at A and end at Z.
 
with it being a continental 220 and I was told it has 520 gitzo? heads will I or should I go ahead and replace the head? the valves appeared to be working last night we could even see the piston moving but 0 compression, when I removed a valve cover I found pieces of metal that looked like ring material, is there a chance that my head is still good? shouls I go ahead and get a new piston too while I am in there? and are there any recomendations on where to get my parts?

thanks,
Aaron
 
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