anyone know about OMC engines-84 Carver

[gugubica]

I am having a weird problem with the Carver.

Twin 350 OMCs.

Port engine fires up instatly and runs great.

Starboard engine starts (not as easily) and runs well, but willl not restart when it is warm or hot.

It is flooded as soon as you turn it off.

Carb problem, right? But wait. I switched the carbs and each engine performs exacly the same.

What else could it be if its not the quadrajets?

 

[High Binder]

Re: anyone know about OMC engines-84 Carver

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gugubica</div><div class="ubbcode-body">I am having a weird problem with the Carver.

Twin 350 OMCs.

Port engine fires up instatly and runs great.

Starboard engine starts (not as easily) and runs well, but willl not restart when it is warm or hot.

It is flooded as soon as you turn it off.

Carb problem, right? But wait. I switched the carbs and each engine performs exacly the same.

What else could it be if its not the quadrajets? </div></div>

Wow, where to begin, Ironically I had these same engines with OMCs as well. In fact I have a spare Full-harness with fuse block that I never used if you want it. With limited details it sounds like you might be vapor locking not flooding. Did you take off the bowl and actually see fuel? Did you pull the plugs to see if they are wet/fouled?

 

[The Mechanic]

Re: anyone know about OMC engines-84 Carver

I am not familiar with OMC but I can run a Q-Jet in my sleep. I have to take a WILD guess and ASSume that it also has a HEI ignition. If it does than you may want to pull the cap off and swap the distibutor caps.
That will swap the coil from one to the other. There are issues with the coils failing (I won't go into it) but shouldn't take you more than 5 minutes with a screwdriver to do. Mark them plug wires. If the problem swaps than go pick yourself up a high quality caps and coils for both and keep the good one in the boat as an emergancy spare.

 

[gugubica]

Re: anyone know about OMC engines-84 Carver

If I open the secondaries I can see fuel puddling on the intake.

I do need to pull the plugs to double check, but they are a royal bitch to get out (exhaust manifolds cover the plugs).

I will admit, that I had not considered vapor lock.

Thanks for the comments, I am out of ideas and need some brainstorming!

 

[gugubica]

Re: anyone know about OMC engines-84 Carver

mechanic, I wish. It has external coils but does have electronic distributers.

I have verified that the coil is getting 12v and it is sending spark to the distr. The distributer is sending spark to the individual plugs.

All verified with a timing light.

Thanks again guys

 

[High Binder]

Re: anyone know about OMC engines-84 Carver

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gugubica</div><div class="ubbcode-body">If I open the secondaries I can see fuel puddling on the intake.

I do need to pull the plugs to double check, but they are a royal bitch to get out (exhaust manifolds cover the plugs).

I will admit, that I had not considered vapor lock.

Thanks for the comments, I am out of ideas and need some brainstorming! </div></div>

Let us (The Mechanic and I seem to be the motor-heads around here) know what you find. I would start with the plugs and look for oil/fuel if they look like shet you might as well just replace them. I know the heads are in the worst spot but that's part of the fun of owning a boat right? Either way, having had this same engine set-up, I would look for vapor lock as being your hard-start situation. If it is the case just re-route that fuel line. You might even check to make sure the cables aren't in a bind somewhere which could cause the one motor to be in a choke situation.

 

[High Binder]

Re: anyone know about OMC engines-84 Carver

I have a spare prop in addition to he wiring harness too you can have both for free.

 

[The Mechanic]

Re: anyone know about OMC engines-84 Carver

A good check on a fuel problem is during the problem "cranking when hot" shut everything off and using a wood coffee stir stick or some other form of small diameter probe. Stick it down the vent tube and compare fuel bowl heights. If there is a significant difference high or low between the two then it is fuel delivery or fuel control (needle and seat) Have had some problems with carbs years ago that was due to the new oxygenated fuels causing the butyl rubber to melt and either stick the needle an seat (not start, no fuel in bowl) to a rich fuel at start from fuel leakage around the seat from pressure build up in the tank and fuel lines from fuel expansion.
You said that it has external coil or coils. Does it have a single coil, or multi coil? If it is single coil than you need to take the power side connector off of the coil and check the power side for burning. Also the coil itself can have the female terminal in the coil hogged out. Unfortunatly the only way to check it to have a handy terminal you can stick in the holes and check for proper tension. The single coils are common to fail and the multi coil are very uncommon to fail.

 

[High Binder]

Re: anyone know about OMC engines-84 Carver

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: The Mechanic</div><div class="ubbcode-body">A good check on a fuel problem is during the problem "cranking when hot" shut everything off and using a wood coffee stir stick or some other form of small diameter probe. Stick it down the vent tube and compare fuel bowl heights. If there is a significant difference high or low between the two then it is fuel delivery or fuel control (needle and seat) Have had some problems with carbs years ago that was due to the new oxygenated fuels causing the butyl rubber to melt and either stick the needle an seat (not start, no fuel in bowl) to a rich fuel at start from fuel leakage around the seat from pressure build up in the tank and fuel lines from fuel expansion.
You said that it has external coil or coils. Does it have a single coil, or multi coil? If it is single coil than you need to take the power side connector off of the coil and check the power side for burning. Also the coil itself can have the female terminal in the coil hogged out. Unfortunatly the only way to check it to have a handy terminal you can stick in the holes and check for proper tension. The single coils are common to fail and the multi coil are very uncommon to fail. </div></div>

O cool stick idea!

It should be a single coil pack. Hopefully one of these ideas will solve his problem. My vote is to swap the 5.7 with a 454.

 

[The Mechanic]

Re: anyone know about OMC engines-84 Carver

A couple of these
GM part number 19201990
or a couple of these
GM part number 19201334
both have a factory warranty!

 

[High Binder]

Re: anyone know about OMC engines-84 Carver

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: The Mechanic</div><div class="ubbcode-body">
GM part number 19201334
both have a factory warranty! </div></div>

Rat style! 572 would launch this boat into orbit!

 

[The Mechanic]

Re: anyone know about OMC engines-84 Carver

All you have to do is push the button "add to cart"

 

[gotbull]

Re: anyone know about OMC engines-84 Carver

Are these the big distributor cap hei.s. and is the module under the cap? Or external? If swapping caps doesn't change things. Could be module.

 

[High Binder]

Re: anyone know about OMC engines-84 Carver

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: The Mechanic</div><div class="ubbcode-body">All you have to do is push the button "add to cart" </div></div>

It's asking for a credit card... what's your number again? You don't mind if I order five of them do you?

 

[gugubica]

Re: anyone know about OMC engines-84 Carver

Update

I have pretty much ruled out vapor lock. It would not restart last night and the temp of the fuel line was only 127 degrees (lazer thermo). Shouldn't be enough to vaporize fuel.

Mech, sorry it has single coils, but there are two engines, hence the plural.

I did not get a chance to pull the plugs. I am going to check fuel pressure tonight. Anybody know what pressure the qjets like?

Unfortunately, I don't think anything would get this boat to warp speed, she's a big un.

More info- carbs recently rebuilt, compression and leakdown tests both OK.

Thanks again for the ideas.

 

[High Binder]

Re: anyone know about OMC engines-84 Carver

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gugubica</div><div class="ubbcode-body">Update

I have pretty much ruled out vapor lock. It would not restart last night and the temp of the fuel line was only 127 degrees (lazer thermo). Shouldn't be enough to vaporize fuel.

Mech, sorry it has single coils, but there are two engines, hence the plural.

I did not get a chance to pull the plugs. I am going to check fuel pressure tonight. Anybody know what pressure the qjets like?

Unfortunately, I don't think anything would get this boat to warp speed, she's a big un.

More info- carbs recently rebuilt, compression and leakdown tests both OK.

Thanks again for the ideas. </div></div>

LEt us know about the plugs.

 

[The Mechanic]

Re: anyone know about OMC engines-84 Carver

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gugubica</div><div class="ubbcode-body">Update

I have pretty much ruled out vapor lock. It would not restart last night and the temp of the fuel line was only 127 degrees (lazer thermo). Shouldn't be enough to vaporize fuel.

Mech, sorry it has single coils, but there are two engines, hence the plural.

I did not get a chance to pull the plugs. I am going to check fuel pressure tonight. Anybody know what pressure the qjets like?

Unfortunately, I don't think anything would get this boat to warp speed, she's a big un.

More info- carbs recently rebuilt, compression and leakdown tests both OK.

Thanks again for the ideas.</div></div>

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">You said that it has external coil or coils. Does it have a single coil, or multi coil? If it is single coil than you need to take the power side connector off of the coil and check the power side for burning. Also the coil itself can have the female terminal in the coil hogged out. Unfortunately the only way to check it to have a handy terminal you can stick in the holes and check for proper tension. The single coils are common to fail and the multi coil are very uncommon to fail.

</div></div>
When I said this I meant 1 coil per motor. So this may be your problem as it was VERY common to have a failed coil and or the coils terminals are all hogged out and lost their tension, requiring replacement. A fast switch of coils should diag this fast with very little effort. Also pop the coil wire off and verify there is not an accumulation of white powder under the coil or cap side. If so it will need a new coil wire if you want to go cheap or a wire set, cap, and rotor if you want to do it right. X2 of course, you should to things like maintenance in pairs.
almost forgot most carbs like 4 psi 5 is pushing it unless you have modified it for higher pressure. Under heavy load it shouldn't go below about 3psi

 

[High Binder]

Re: anyone know about OMC engines-84 Carver

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: The Mechanic</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gugubica</div><div class="ubbcode-body">Update

I have pretty much ruled out vapor lock. It would not restart last night and the temp of the fuel line was only 127 degrees (lazer thermo). Shouldn't be enough to vaporize fuel.

Mech, sorry it has single coils, but there are two engines, hence the plural.

I did not get a chance to pull the plugs. I am going to check fuel pressure tonight. Anybody know what pressure the qjets like?

Unfortunately, I don't think anything would get this boat to warp speed, she's a big un.

More info- carbs recently rebuilt, compression and leakdown tests both OK.

Thanks again for the ideas.</div></div>

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">You said that it has external coil or coils. Does it have a single coil, or multi coil? If it is single coil than you need to take the power side connector off of the coil and check the power side for burning. Also the coil itself can have the female terminal in the coil hogged out. Unfortunately the only way to check it to have a handy terminal you can stick in the holes and check for proper tension. The single coils are common to fail and the multi coil are very uncommon to fail.

</div></div>
When I said this I meant 1 coil per motor. So this may be your problem as it was VERY common to have a failed coil and or the coils terminals are all hogged out and lost their tension, requiring replacement. A fast switch of coils should diag this fast with very little effort. Also pop the coil wire off and verify there is not an accumulation of white powder under the coil or cap side. If so it will need a new coil wire if you want to go cheap or a wire set, cap, and rotor if you want to do it right. X2 of course, you should to things like maintenance in pairs.
almost forgot most carbs like 4 psi 5 is pushing it unless you have modified it for higher pressure. Under heavy load it shouldn't go below about 3psi </div></div>

+1 on Mech's post