An Engine Issue

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dcmore4787
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An Engine Issue

Post by dcmore4787 »

I have a 1988 F321 with 2 350 CID Engines. A warm compression test shows between 115 and 120, which is either cold or warm. Both Engines sound very good, both have Electronic Ignitions and a new tune up. The plugs on the Starboard motor showed that it was burning rich so I did an adjustment on the carburetor, turning both needles out by 1.5 turns as a starting point. I will add that the issue that I am having was before this adjustment.
The issue that I am having is that the Starboard Engine needs more throttle to reach the same RPM as the Port Engine. The RPM range was 2550 to 2700.
I have run the engines at WOT because I didn't think to overburden the Engines. They both have approx. 1500 hours on them and they are within 2 hours of each other. I am seeing that the starboard Engine is consuming more fuel. I have installed new control cables, however as I am writhing this I have not checked the distance of travel on the linkage. This issue was happening with the old cables any way so It didn't come to mind.
A thought that I had was the carburetor accelerator pump or the carburetor it self or a related fuel issue. The fuel filters are clean and there are new fuel pumps.
I would appreciate any input, and I thank you in advance.
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captainmaniac
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Re: An Engine Issue

Post by captainmaniac »

Check timing / advance. I had an issue a few years back where one of my distributors was not advancing properly so the engine just couldn't build up rpms no matter how far I pushed the throttle. Distributor rebuild fixed it.
mrrudely
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Re: An Engine Issue

Post by mrrudely »

I agree with captainmaniac
I would check the advance curve first
also check the plugs again
I don't see how the accelerator pump would have anything to do with it
I did not understand "I have run the engines WOT because I didn't think to overburden the Engines."
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dcmore4787
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Re: An Engine Issue

Post by dcmore4787 »

I meant I have not ran it wot

Thank you, the distributor was changed a long time ago. I think of that thank you. I am going to order 2 new electronic distributors and give that a try. I will let you how that works.
mrrudely
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Re: An Engine Issue

Post by mrrudely »

I recently changed my distributors to HEI
while the engines are right and left rotation
the distributors are not, they were both the same rotation
maybe common knowledge but thought this might be helpful
also you might want to consider rebuilding the carburetor first if the advance curve checks out
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dcmore4787
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Re: An Engine Issue

Post by dcmore4787 »

I appreciate all the input, thank you. I will start by installing new distributors. I had mentioned the accelerator pumps thinking that they were not holding pressure suppling the jets with gas. A rebuild may be a good idea.
dcmore4787
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Re: An Engine Issue

Post by dcmore4787 »

Captainmaniac you were correct a broken spring in the distributor
I am changing the Mallory to a pertronix distributor
Thank you for the insite
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oldboat1
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Re: An Engine Issue

Post by oldboat1 »

It sounds like you enriched the mixture (counter-clockwise). For a leaner setting, you would turn clockwise.
Motors should run. People -- not so much.

1980 F26, Mercruiser 305
1979 14' Starcraft, 1957 18 hp Evinrude and '57 3hp Evinrude kicker
larryeddington
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Re: An Engine Issue

Post by larryeddington »

changed my distributors for aftermarket and now work perfectly, it was the advancing apparently
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larryeddington
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Re: An Engine Issue

Post by larryeddington »

larryeddington wrote: Wed Jun 05, 2024 3:18 pm changed my distributors for aftermarket and now work perfectly, it was the advancing apparently. replaced with petronix
Larry Eddington
1984 F-36 Tri Cabin "The Phoenix II"
1978 F-28 "The Phoenix"
Fish Master 2350 Bay Boat
9.5' Dink
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