WOT not reached after rebuild

[jimmbo]

I don't know about the timing advancing.
I believe I have a small hook bottom.
The stringers transom and foam were waterlogged. some areas were bad and some were ok.
The cam was bought on ebay and I compared the two camshafts. Plus it had the cam lobe for the mechanical fuel rod.

A hook can knock several MPH off the top speed, and it doesn't need to very large at all.

Did you remove all the soaked foam?

New or Used Cam? VP, Mercrusier part #s
How did you compare them? Even my my Micrometer Eyes have trouble measuring Duration and Lift. 1990, that would be Pre Vortec.

 

[Chris51280]

A hook can knock several MPH off the top speed, and it doesn't need to very large at all.

Did you remove all the soaked foam?

New or Used Cam? VP, Mercrusier part #s
How did you compare them? Even my my Micrometer Eyes have trouble measuring Duration and Lift. 1990, that would be Pre Vortec.

Total gut job.
Well, then I don't really know if it was a true mercruiser cam. It was sold as such.
It is pre-vortec without the balance shaft.

 

[Chris51280]

Looking at the numbers, it appears to be correct. The bottom anti fouling will slow me down and I think the weight is a significant factor. The 4 blade turning point is probably a bit aggressive and the 2bbl carb is not the best either vs 4bbl. I think i need to clean the bottom up when ever I get to it and try a 14x17 prop. I will also check the compression and the firing of all cylinders

 

[Chris51280]

So I checked the compression cold at 130 to 140 psi. Not sure how accurate the gauge is but 4 cylinders were at 135psi
I checked with all plugs out. Could not tell much by the plugs since they are new with only 3 hours on them

I took several videos of it running at idle.

What i noticed now is a slight knock ob top. And when I take the plug wire #1 and #3 off there seems to. E no difference. The others I can tell it changing tone at idle when I unplug them. Any thoughts. Also, the resistor sparks when I unplug the wires, is this normal?

 

[Chris51280]

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[Chris51280]

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[jimmbo]

Are all the plug wires going to the proper cylinder?
The sparking when the plug wires are pulled is not normal. Is the that HT wire fully inserted in the coil? Is the insulator cap damaged? Is the coil housing where the HT wire damaged or cracked?
You appear to have good spark at the coil, but will it jump a 7/16" gap at the spark plug end? Are there any cracks in the spark plug insulators?

 

[Chris51280]

spark plugs are new from the marina. they are ngk br6.

I will double check the wires if they are 100% connected and correctly as well.
I will check the coil wire again too
The cap seemed to be ok without any visual crack.
I can check if it will jump 7/16 tomorrow as well.

It actually is cylinder #1 and #5 that does not appear to fire. Tha would explain loss of power. It just is very interesting that running without 2 cylinders it runs this "smooth"

 

[Chris51280]

Another thing I found out today. Not sure if you can confirm. Since my decals are gone on the side I could not find the gear ratio and always assumed it is the 1.84:1 ratio. My sterndrive number is however 0D463089 which puts me in a 1.98:1 ratio. Is this better or worse?
apparently this was an optional outdrive for my engine back then

 

[jimmbo]

New plugs can get cracked insulators, when installed.
The difference in the Gear Ratio means you will need slightly more Pitch on the prop than with a 1.84:1. Alternate ratios were offered for heavier than usual boats, and/or High Altitude locations. The reason is to reduce the narrow/reduce the range of Pitches used, even if one boat has a v6, the other a 4 and a third a v8

 

[alldodge]

was rebuild over the winter

if the valves are not adjusted properly and hanging up, you would be low on compression.

So I checked the compression cold at 130 to 140 psi. Not sure how accurate the gauge is but 4 cylinders were at 135psi

Sure sounds like its doing worst then the old motor and the low compression will do just that. So as Scott mentioned maybe check your valve adjustment first

 

[Chris51280]

New plugs can get cracked insulators, when installed.
The difference in the Gear Ratio means you will need slightly more Pitch on the prop than with a 1.84:1. Alternate ratios were offered for heavier than usual boats, and/or High Altitude locations. The reason is to reduce the narrow/reduce the range of Pitches used, even if one boat has a v6, the other a 4 and a third a v8

That would explain the 23p ss prop that was on there.

 

[Chris51280]

I checked the wires today and it appeared that cylinder 1 and 5 were switched. It runs alot smoother now and accepts the throttle alot better. It sounds more powerful. I will try out on the weekend when the weather is better.

 

[Chris51280]

Went to lake Erie to try her out. Afyer dropping the admiral off with the kids I opened her up and boy what a difference 2 more cylinders make lol. I got 4500 rpm and around 40mph. It was a bit choppy and windy so I could not trim her out but i think I can get close to 42-43mph. Will try again next time with calmer waters.

 

[jimmbo]

Glad it's running better