OnSiteEquipment
Recruit
- Joined
- Jul 9, 2019
- Messages
- 3
Hello all, new to the forum.
Twin engine boats are new to me so this is where I found I need help.
The boat is a 88 Nova Spyder 26ft twin 350 alpha 1 gen 1 drives with 23 pitch marage props.
I got the boat with two cracked engines. One I replaced with a low mileage truck/rv engine and swapped all the marine components over. The other has been, to this point so far, successfully expoxied. Both engines have been out of the boat. Drives got new oil pumps and bellows.
The problem: both engines are synced within 200rpm of each at any throttle position, planes off instantly and shoots out of the hole, but at 45mph it reaches 3600 rpm and holds it. Nearly on the dot.
What I know:
Good ignition, timing advance working as it should, base timing set to 8* btdc in both
Props are sized correctly to the boat 14 5/8x23, wellcraft forums highly recommend the marage 23 on this Hull
New intake gaskets on both engines.
Rpms varied via external tach on timing gun.
Secondaries are mechanically opening, (Weber carbs I believe) vacuum seems to hold the upper air flap closed on the secondaries, which from my understanding has counter weights and air flow opens them, they move freely.
Both engines have vr1 racing oil straight 50w
Compression on both engines is between 150-160psi with the exception of one cylinder on the new engine at 140psi.
The engines both start easy, run smoothly at idle as well under load.
The only thing that tells me there is a problem is experience, this boat should do 60mph and be turning mid 4000s rpm.
I could of sworn the new engine for the first few minutes on the water would do more rpm, and would need less throttle then the other engine to maintain same rpm, but now here we are that both are behaving the exact same, so I know the problem is shared between them.
Thoughts??
Twin engine boats are new to me so this is where I found I need help.
The boat is a 88 Nova Spyder 26ft twin 350 alpha 1 gen 1 drives with 23 pitch marage props.
I got the boat with two cracked engines. One I replaced with a low mileage truck/rv engine and swapped all the marine components over. The other has been, to this point so far, successfully expoxied. Both engines have been out of the boat. Drives got new oil pumps and bellows.
The problem: both engines are synced within 200rpm of each at any throttle position, planes off instantly and shoots out of the hole, but at 45mph it reaches 3600 rpm and holds it. Nearly on the dot.
What I know:
Good ignition, timing advance working as it should, base timing set to 8* btdc in both
Props are sized correctly to the boat 14 5/8x23, wellcraft forums highly recommend the marage 23 on this Hull
New intake gaskets on both engines.
Rpms varied via external tach on timing gun.
Secondaries are mechanically opening, (Weber carbs I believe) vacuum seems to hold the upper air flap closed on the secondaries, which from my understanding has counter weights and air flow opens them, they move freely.
Both engines have vr1 racing oil straight 50w
Compression on both engines is between 150-160psi with the exception of one cylinder on the new engine at 140psi.
The engines both start easy, run smoothly at idle as well under load.
The only thing that tells me there is a problem is experience, this boat should do 60mph and be turning mid 4000s rpm.
I could of sworn the new engine for the first few minutes on the water would do more rpm, and would need less throttle then the other engine to maintain same rpm, but now here we are that both are behaving the exact same, so I know the problem is shared between them.
Thoughts??
