loss of power, increase in RPM

[Ciera2450]

Re: loss of power, increase in RPM

btw, I was reading more about the coil and it seems that the resistance readings DO NOT necessarily mean the coil is functioning properly. Is there a way to further test it other than a new one?

 

[bruceb58]

Re: loss of power, increase in RPM

As for the timing, I set 8deg. BTDC and did NOT check the advance timing. Which if my thinking is correct(and as bruce58 stated) the automotive dist. uses a vacuum advance that isn't even hooked up and has never been since i've owned the boat. Its very likely then that the timing advance isn't my problem....right?

You are not going to be getting full advance so that definitely is a problem.

Some auto stores will loan them.

If you have a Harbor Freight near you, they will have one.

 

[Ciera2450]

Re: loss of power, increase in RPM

Bruce58, the motor ran "normally" for approx. 200hrs the past two seasons with the set up in there. While not the correct set up, it did function. I agree the distributor needs replaced with the correct one regardless and that is #1 on my list of parts.
Going to pick up compression tester now. I'll post back later today with numbers.

 

[Ciera2450]

Re: loss of power, increase in RPM

maybe a dumb question...

I can test the compression with the valve covers removed right?

 

[captmello]

Re: loss of power, increase in RPM

I would put the covers on loosely just to keep the oil in the motor since the oil pump will be pumping while you crank.

All plugs removed, throttle wide open...

 

[bruceb58]

Re: loss of power, increase in RPM

Bruce58, the motor ran "normally" for approx. 200hrs the past two seasons with the set up in there. While not the correct set up, it did function. I agree the distributor needs replaced with the correct one regardless and that is #1 on my list of parts.
Going to pick up compression tester now. I'll post back later today with numbers.

OK...didn't realize that.

 

[Ciera2450]

Re: loss of power, increase in RPM

Ok guys....compression numbers...
Cylinder 1=145
Cylinder 3=140
Cylinder 5=150
Cylinder 7=145
Cylinder 2=138
Cylinder 4=151
Cylinder 6=140
Cylinder 8=122

I put oil in cylinder 8 and tested again....the reading was the same if not a tiny bit lower. The guage reads in 5psi increments so I had to eyeball a few readings.


What is my next step here guys? Bad valves?

 

[bruceb58]

Re: loss of power, increase in RPM

Cylinder leak down test on that cyclinder might be nice to try to see if its a valve or head gasket.

 

[Ciera2450]

Re: loss of power, increase in RPM

Thank you sir. I appreciate the help! I'll see if I can get that done.

 

[Ciera2450]

Re: loss of power, increase in RPM

I always like an excuse to buy more tools.
However, couldn't I remove the heads and visually inspect the valves and gasket?

 

[bruceb58]

Re: loss of power, increase in RPM

I always like an excuse to buy more tools.
However, couldn't I remove the heads and visually inspect the valves and gasket?

Assuming the valve lash on that cylinder is correct. Has that ever been touched?

 

[captmello]

Re: loss of power, increase in RPM

I'm not sure what chasing down that leaky valve is going to do to help your running issue. Although there is clearly a weak link in that cylinder, i don't think it is your running issue.

What's your next move?

 

[bruceb58]

Re: loss of power, increase in RPM

I'm not sure what chasing down that leaky valve is going to do to help your running issue. Although there is clearly a weak link in that cylinder, i don't think it is your running issue.

What's your next move?

I think I may agree. Its a little low but may not be your problem.

 

[Ciera2450]

Re: loss of power, increase in RPM

Not to my knowledge. I haven't touched the valve train.....yet.

The cylinder leak down tester isn't all that cheap. So I may just start breaking the motor down to find the problem..... I'll likely have to anyways it seems. Is this a bad idea???

I'm thinking a broken head gasket will appear obvious when I get down to it. I will take plenty of pictures along the way to get everyones advice/opinions.

Any other precautions or things to look out for?

 

[Ciera2450]

Re: loss of power, increase in RPM

Posting at the same time...

Uh oh.... now ya got me thinking captmello.... Maybe I better slow down.
I'm unsure what else to test or check. I'm getting spark, fuel, and air. I suppose I could get that new distributor set up and see what happens. Even tho the distributor on there is wrong, everything tests ok...

Any advice on what to do?

Thanks all for the help!

 

[Tail_Gunner]

Re: loss of power, increase in RPM

Thanks for the reply captmello

with the automotive distributor thats in there, there is what I believe to be a vacuum advance but its not hooked up to anything and is capped off. It has never been hooked up.
Is there something else that would control timing advance?

OK see that orange part top right...now see the alum pic below....the below pic is a vacum advance is it hooked up (orange thing) to a vacum line....its been so long... Id bet its not and if it is. You just unhook the thing and your engine should bog a bit.

 

[Ciera2450]

Re: loss of power, increase in RPM

It isn't hooked up to a vacuum hose. It never has been. While not correct, the motor did run normally this way before....

 

[Tail_Gunner]

Re: loss of power, increase in RPM

Pics are not clear enough..is the advance module hooked the dist..If so hook it up thats the issue

 

[Ciera2450]

Re: loss of power, increase in RPM

Yes the advance module comes out of the distributor. However, it has not been hooked up since i've owned the boat. The motor has run fine without it for the two years i've had it. Could it suddenly start causing the issue's i'm having? I do plan to order the delco est dist. system and replace the incorrect automotive one. I guess that would eliminate the timing advance and distributor as an issue. Everything else in the ignition system has been replaced, may as well finish it off and see if that solves the issue. I honestly don't know what else to do at this point.

 

[Tail_Gunner]

Re: loss of power, increase in RPM

Yes the advance module comes out of the distributor. However, it has not been hooked up since i've owned the boat. The motor has run fine without it for the two years i've had it. Could it suddenly start causing the issue's i'm having? I do plan to order the delco est dist. system and replace the incorrect automotive one. I guess that would eliminate the timing advance and distributor as an issue. Everything else in the ignition system has been replaced, may as well finish it off and see if that solves the issue. I honestly don't know what else to do at this point.

Hook it up: http://www.73-87.com/7387garage/drivetrain/hei.htm Simple little vacum tube from the carb....I know that carb has vacum ports....maybe...I cannot imagine have a vacum advance module and its not functional....but then this is a boat...